Servicescape design of leisure spaces such as theme parks influence the level of visitor satisfac... more Servicescape design of leisure spaces such as theme parks influence the level of visitor satisfaction and the re-visitation rate. However, only a few large theme park operators have a separate theme of specialists with heuristic knowledge for servicescaping. In response, small companies turn to the specialists paying high fees and royalties usually leading to outdated servicescape designs. In order to help small companies to design servicescape that provide satisfying experience to the visitors, a systematical understanding of the multi-layered and complex service environment of theme parks is necessary. The purpose of this research is to integrate the concept of precedent-based design into a rule-based system by identifying and organizing the design patterns of servicescape into reusable knowledge, propose a ser-vicescape design support system, and confirm whether if the system helps to increase designers' credence regarding their design in terms of its market success. To accomplish these research aims, six steps were carried out: (1) selection of globally accepted facilities for being successful, (2) analysis of precedents for the discovery of repeating servicescape design patterns, (3) knowledge acquisition and organization for each design patterns, (4) formulation of servicescape rules using the acquired and organized knowledge, (5) integration of the rules into a general design process of a facility as a system, and (6) application of the system in practice. The resulting system was presented to an expert in the field of theme park designs to confirm whether the design process is applicable and how it will perform in practice. From this interview, we received positive feedbacks and well as feedbacks for improvements in the aspects of the system's applicability in practice, its functionality, and usability. After confirming the applicability of the overall process of the system, we conducted an experiment to experts in practice from various design and planning fields and asked to go through two sets of scenarios in which the first is to design a given site without the system and the second is to design the same site with the system. After each scenario, the subjects were asked to fill out a revised After-Scenario Questionnaire (ASQ). From this experiment, the results indicate that the subjects felt an increase in their credence toward their designs in terms of its market success while the satisfaction with the easiness and the time it took decreased. If our system is revised in the aspects of usability and functionality, our system which uses precedent design patterns could be used to help small company designers to produce servicescape concept designs with more design credence.
Digital games are generating various types of virtual landscape and the importance of virtual lan... more Digital games are generating various types of virtual landscape and the importance of virtual landscape has been arises. However, there has not been any research done how to design the virtual landscape. To establish virtual landscape design methodology, establishing the classification system and suggesting the representative type of virtual landscape is needed. With this research, I collected the classification standard and established five standards; story, cooperation, interaction level, dimensions and shape of the space. With that system, I classified digital game and could prove the effectiveness. Also by classifying cases through 20 years of timeline, I could come out with three representative types. This result will work as a reference to the future research; establishing design methodology on virtual landscape.
Design experience from previous design cases could help designers solving current design problems... more Design experience from previous design cases could help designers solving current design problems. Therefore, a case-based recommender system can recall suitable design cases for designers based on a similarity measurement mechanism. In the context of Product-Service System (PSS) design, the measurement of similarity between different cases becomes more challenging because of the complex nature of the PSS design. In this research, we propose a similarity measurement framework of PSS design cases based on the context-based activity model. In the proposed framework, a PSS design case is indexed and quantified by design activity element, design process, and function requirement. Ways to measure similarity between design indexes and design cases are also specified. A case study along with an empirical validation was conducted to validate the framework.
Bio-inspired design was introduced as an alternative method to encourage breakthrough innovations... more Bio-inspired design was introduced as an alternative method to encourage breakthrough innovations during design projects by stimulating analogical reasoning and thinking of designers. However, the method did not perform as well as researchers expected because most designers, who are novices in the fields of biology and ecology, cannot infer the proper analogue (i.e. biological system) from nature. To resolve this fundamental problem, a causal model based representation framework for 'analogical reasoning' – searching and selecting the biological systems to apply – have been developed. In addition, ontology based repository structures and retrieval systems have been proposed to support 'analogical thinking' of designers. Nevertheless, these systematic approaches still restrict the candidates and inevitably lose potential biological systems relevant to the design project, due to the 'physical relation' biased problem and the ambiguity of the indexing mechanism of both current representation frameworks and retrieval systems. For example, the causality based support system known as a robust representation framework for a single biological system, stores information of a biological system only by its internal 'physical relations' and retrieves biological systetabms only by the physical relevance. However, from the perspective of ecological thinking, the further relatedness of 'physical, biological, and ecological relations' composes the holistic concept used to identify an organism in the flow of evolution because the 'biological and ecological relations' are also involved in the traits that designers may be interested in. Therefore, the supplementary information for 'biological and ecological relations' must be added to index the biological and environmental interactions, and to use the connectivity among entire organisms in the retrieval process. In this research, a causality based holistic representation framework for biological systems and an 'all-connected' ontology based repository and retrieval system are developed as a knowledge-based recommendation system to support bio-inspired design. The knowledge-based system we developed allows engineering designers to search and select a particular biological system and extract design strategy without much biological knowledge. This effort provides more opportunities in a bio-inspired design process by adding potential biological systems that might previously not have been considered.
This study proposes an advanced thermal control method that employs artificial neural network (AN... more This study proposes an advanced thermal control method that employs artificial neural network (ANN) models for predictive and adaptive thermal control. Two predictive and adaptive control logic approaches were proposed to simultaneously control indoor temperature and humidity as well as predicted mean vote (PMV) in a residential building. Their thermal performance was analysed and compared with that of non-ANN-based counterparts to evaluate architectural variables such as envelope insulation and building orientation. A numerical computer simulation method was used for the tests after demonstration of its validity based on comparison with results of field measurement. Analysis results revealed that the proposed predictive and adaptive control methods conditioned the indoor temperature, humidity and PMV effectively. The periods during which each thermal factor was in a comfortable range increased, and overshoots and undershoots out of the targeted comfortable ranges were reduced when using the ANN model. The results demonstrate the functionality of the proposed method for variation in architectural variables and that the ANN model has the potential to be successfully applied to building thermal controls.
Owing to the incredible increase in the amount of information on the World Wide Web, there is a s... more Owing to the incredible increase in the amount of information on the World Wide Web, there is a strong need for an efficient web page classification to retrieve useful information quickly. In this paper, we propose a novel simplified swarm optimization (SSO) to learn the best weights for every feature in the training dataset and adopt the best weights to classify the new web pages in the testing dataset. Moreover, the parameter settings play an important role in the update mechanism of the SSO so that we utilize a Taguchi method to determine the parameter settings. In order to demonstrate the effectiveness of the algorithm, we compare its performance with that of the well-known genetic algorithm (GA), Bayesian classifier, and K-nearest neighbor (KNN) classifiers according to four datasets. The experimental results indicate that the SSO yields better performance than the other three approaches.
Understanding how similar design appears is a key element to understanding companies’ design stra... more Understanding how similar design appears is a key element to understanding companies’ design strategies. However, it is difficult to evaluate companies’ design strategies with conventional style measurement methods since they only taxonomically measure whether a specific characteristic is included in a specific style. This study numerically measured car design similarities to synthesize and analyze car brand styles, thereupon discovering the design trends among car brands for strategic design positioning. This paper aims to find methods for quantifying style differences and identifying unique design elements of car designs among 23 automobile manufacturers based on design similarities of a large quantity of car designs (N = 119). To achieve this goal, a hybrid style quantification methodology – a mixture of Fourier decomposition, eye tracker, and shape grammar – was created to evaluate similarities, visual significance, and combinations of 19 car design elements. Fourier decomposition was incorporated to find the quantifiable values of design similarities of car design elements. Visual significance analysis was also conducted for each car design element through eye tracker to measure the importance of certain design elements for weighting factors. Then, each combination of design elements was compared with car design elements of other cars for similarity calculations. Finally, car design alternatives were synthesized, and transitions of design positioning were analyzed based on the similarity values weighed by the visual significance results. Using the suggested methods, alternate designs can be synthesized while preserving brands’ design styles, and design trends can be analyzed for strategic evaluation.
This study aims to develop and validate an annual photosensor performance simulation method (APPS... more This study aims to develop and validate an annual photosensor performance simulation method (APPSM) to compute the photosensor signals for a lighting control system under various daylight conditions. A series of computer simulations using PSENS, which is a simulation program within Radiance software were conducted and field measurements were performed under various daylight conditions in order to validate the simulation results of APPSM.
Results indicate that the photosensor signals predicted by PSENS and APPSM showed a strong linear correlation. Prediction results by APPSM generally consisted with the results field measurements, although slight differences between them existed under particular daylight conditions. The differences in photosensor signals between the prediction by APPSM and measurement effectively decreased as shielding conditions were applied to photosensors.
A strong linear relationship existed between the photosensor signals obtained from prediction by APPSM and the field measurements. The prediction models for the photosensor shielding conditions were acceptable with a significance level of 0.01. The majority of percent differences between the measured and simulated photosensor signals were within 10% under clear and partly cloudy sky conditions.
Virtual game controllers are essential for particular game genres where the game contents are tra... more Virtual game controllers are essential for particular game genres where the game contents are transplanted from various platforms into a smart-phone platform. Virtual images are projected as a game interface at the smartphone’s output screen. Therefore, a certain amount of space needs to be abandoned for the controller’s interface projection. In addition, the functions of the game contents are fundamentally limited, thus eliciting the necessity of a limited number of buttons. In this study, diverse types of interaction that occur between the user and touch-screen were researched, and adequate interactions for smart-phone game contents were extracted and analyzed. In addition, the focus is placed on minimizing the number of controller buttons while including diverse functions at the contents level. Notably, the study pointed out that previous virtual game controllers are a mere metaphor of traditional methods, thus limited to Tap interaction. By analyzing fighting action game contents, the Tap interaction is enhanced by adding Flick and Multi-touch interaction to diversify and enhance previous interaction values. Finally, a prototype was developed by ameliorating past interfaces and referring to the intrinsic features of the aforementioned types of interaction, followed by user evaluation. A previous questionnaire method was adjusted to the particular research purpose, and quantitative evaluation was conducted while documenting and analyzing the user-log data of repetitive experiments.
The results show that Flick and Multi-touch interaction techniques are beneficial under a smartphone touchscreen environment beyond the traditional Tap-only. Furthermore, functions are maintained with a minimum number of buttons while the situation compatibility of user interaction is verified. This study also shows that adding diverse types of interaction to the simple Tap-only affords a distinctive user experience of long-term interest and fun to the players that were previously restricted to the accustomed Tap-only. The results authenticate the applicability of the intrinsic fun mechanism to the smartphone based touchscreen game interaction. The study has implications in enhancing the traditional Tap-only based virtual game controller, which is a mere metaphor of controllers loaded onto other platforms, through proposing a tailored interface design and evaluation method under a smartphone platform. Furthermore, this study contributes objective reference source for the engineers to design future game contents, interface and heuristics evaluation in the platform.
Biomimetic design performed to develop a solution-shape has been offered as a successful approach... more Biomimetic design performed to develop a solution-shape has been offered as a successful approach for overcoming the limitations of typical design methods. Especially for the nose-shape of high-speed trains, the morphological characteristics of a superior bio-model were used in the design process. However, current design methods using the biomimetic approach, particularly in the morphological domain, do not support a technique to evaluate how close the new solution is to the optimal one; nor do they support alternative methodologies used to validate and verify the solution-shape being developed. Solution optimization in a biomimetic design means not only preserving the original shape of a bio-model but also validating and verifying it. Shape optimization for a design problem should accompany shape evaluation and modification conducted according to criteria involving both evolutionary traits and technological constraints. In this research we suggest a method to verify the original shape, and to validate the solution, using theoretical backgrounds from both systematic biology and evolutionary biology. In this paper, the morphological characteristics of a bio-model are verified and modified using a quantitative method. To validate the solution developed, new criteria are applied for high-speed-train design.
This study proposes an effective thermal control method for thermally comfortable and energy-effi... more This study proposes an effective thermal control method for thermally comfortable and energy-efficient environments in buildings with double skin envelopes. Four rule-based control logics and an artificial neural network (ANN)-based control logic were developed for the integrated control of openings and cooling systems in summer. Using numerical computer simulations, the performance of the proposed control logics was comparatively tested in terms of thermal performance and energy efficiency.
Analysis results imply that the more detailed rules of thermal control logic were effective to maintain the indoor temperature conditions within comfortable ranges. The ANN-based predictive and adaptive control logic presented its potential as an advanced temperature control method with an increased temperature comfort period, decreased standard deviation of temperature from the center of the comfortable range, and decreased number and ratio of overshoots and undershoots out of the comfort range. The additional rules embedded for control logic or ANN applications yielded a more comfortable temperature environment in an integrated manner according to the properly designed operations of envelope openings and the cooling system. However, logics with additional rules and ANN models consumed more energy for space cooling. Therefore, the rule-based controls with advanced logics or an ANN model are required in case occupant comfort is a primary factor to be satisfied. In other cases, the simple rule-based logic is effectively applied.
This study describes integrated logic for an artificial neural network (ANN) to control heating d... more This study describes integrated logic for an artificial neural network (ANN) to control heating devices on a continuous basis. Two ANN-based control logic systems and two conventional rule-based logic systems were developed to control a heating device and the openings of a double skin enveloped building. The ANN-based logic controls heating devices on a continuous basis according to the indoor temperature. The rule-based logic controls heating systems and openings at envelopes in two-position on/off operation. Control performance for the developed logic was numerically conducted using computer simulations for a small office space with double skin envelopes during the heating season.
Analysis results indicate that the ANN-based temperature control logic resulted in a more stable temperature near the center of the comfortable range with a reduced opening period of the internal envelope. The reduced number of on/off moments of the heating device and the openings in the ANN-based logic were predicted to save energy and prevent system degradation. The use of ANN-based logic would be effective for maintaining a stable thermal environment and for system operation. Rule-based logic can be effectively used to improve building energy efficiency. In this study, two ANN-based logic types were developed for heating devices controlled on a continuous basis and their performance was compared with those of rule-based on/off logic. Thus, in order to cover the limitation of this study, further study is warranted for examining the clear difference achieved by ANN-based vs. rule-based control, when they are applied to control heating output on a continuous basis.
This study aims at developing an indoor temperature control method that could provide comfortable... more This study aims at developing an indoor temperature control method that could provide comfortable thermal conditions by integrating heating system control and the opening conditions of building envelopes. Artificial neural network (ANN)-based temperature control logic was developed for the control of heating systems and openings at the building envelopes in a predictive and adaptive manner. Numerical comparative performance tests for the ANN-based temperature control logic and conventional non-ANN-based counterpart were conducted for single skin enveloped and double skin enveloped buildings after the simulation program was validated by comparing the simulation and the field measurement results. Analysis results revealed that the ANN-based control logic improved the indoor temperature environment with an increased comfortable temperature period and decreased overshoot and undershoot of temperatures outside of the operating range. The proposed logic did not show significant superiority in energy efficiency over the conventional logic. The ANN-based temperature control logic was able to maintain the indoor temperature more comfortably and with more stability within the operating range due to the predictive and adaptive features of ANN models.
Most of the assessment of creativity in product design is based on the outcome, not the design pr... more Most of the assessment of creativity in product design is based on the outcome, not the design process from which the creative ideas are derived. In this paper, we revealed the correlation coefficient of 20 factors critical in the product design process and the quality of design creativity via investigation of the design processes and outcomes of 30 senior student designers. Six closely related factors were identified as variables to calculate the design creativity. An assessment formula was proposed: the corresponding correlation coefficient is the weight factor of each variable, and the sum represents the design creativity degree. Our quantitative approach can improve the validity and reliability of assessment of creativity in product design.
The combined effects of color temperature and illuminance in a small office on visual response an... more The combined effects of color temperature and illuminance in a small office on visual response and mood under various lighting conditions were examined in this study. Visual annoyance tests were conducted using a sample of 20 subjects in a full-scale mock-up test space. Computer and paper-based reading tasks were conducted for 500 lx and 750 lx illuminance levels under 3,000 K, 4,000 K and 6,500 K conditions. Two hypotheses were considered for the test in this study. The primary hypothesis was that visual perception is affected by the color temperatures of light sources. The secondary hypothesis was that better moods, such as relaxed and cozy feelings, are associated with low color temperatures given equal illuminance levels. The visual environment under the 3,000 K condition was characterized by glare and brightness, resulting in visual discomfort when target illuminance was higher than 500 lx. Occupants preferred 500 lx under the 6,500 K condition, and 500 lx and 750 lx under the 4,000 K condition, reporting better visual satisfaction when performing office tasks. Prediction models for visual comfort suggest that the less that subjects are visually bothered by light during tasks, the more visual comfort they feel. User satisfaction with light source color is critical for the prediction of visual comfort under different lighting conditions. Visual comfort was the most influential factor on mood. Lower color temperature was associated with better mood at lower illuminance levels, while higher color temperature was preferred at higher illuminance levels.
The influences of lighting conditions, which is combined by color temperature and lighting types,... more The influences of lighting conditions, which is combined by color temperature and lighting types, on visual responses are discussed in this study. Visual annoyance tests were performed in a full-scale mock-up test space, which was prepared for a small private office environment. Lamps with color temperature of 3,500 K and 5,000 K were applied to a direct lighting type and direct/indirect lighting type. Results indicate that overall glare sensation for computer-based task was stronger than that of paper-based task. Color temperature of 3,500 K applied to a direct lighting type caused the worst glare. Overall, visual discomfort were not reported under all lighting conditions. The direct/indirect lighting type succeeded to ensure better comfort compared to the direct lighting type. The number of letters which were typed in showed no significant difference under all lighting conditions. In order to enhance good quality of lighting condition, the direct lighting type should ensure good color rendering, reduction of glare and prevention of tensed sensation. The direct/indirect lighting type condition should keep the space and desktop surface bright.
This study aims to develop Artificial Neural Network (ANN) models to examine the thermal performa... more This study aims to develop Artificial Neural Network (ANN) models to examine the thermal performance of double skin-enveloped buildings under different opening conditions. Performance tests of the ANN models, which were developed for integrated temperature control logics, were conducted for a space with a double skin envelope in a one-storey building during the winter.
ANN models were embedded in the logic for predictive and adaptive controls in order to ensure comfortable, energy-efficient indoor temperature conditions. Four ANN models were developed to predict future indoor temperatures under different opening conditions of the internal and external envelopes. Their performances were preliminarily tested by comparing them with conventional non-ANN-based methods in terms of thermal control and energy efficiency.
The comparative analysis revealed that the ANN models were properly organized to predict future indoor temperature conditions. Based on the prediction accuracy, the optimal opening conditions and heating system operations could be determined to guarantee advanced methods for effective thermal control and energy efficiency. Thus, ANN models are expected to be applied to the temperature control logic for double skin-enveloped buildings in order to improve their thermal control performance and energy efficiency.
Servicescape design of leisure spaces such as theme parks influence the level of visitor satisfac... more Servicescape design of leisure spaces such as theme parks influence the level of visitor satisfaction and the re-visitation rate. However, only a few large theme park operators have a separate theme of specialists with heuristic knowledge for servicescaping. In response, small companies turn to the specialists paying high fees and royalties usually leading to outdated servicescape designs. In order to help small companies to design servicescape that provide satisfying experience to the visitors, a systematical understanding of the multi-layered and complex service environment of theme parks is necessary. The purpose of this research is to integrate the concept of precedent-based design into a rule-based system by identifying and organizing the design patterns of servicescape into reusable knowledge, propose a ser-vicescape design support system, and confirm whether if the system helps to increase designers' credence regarding their design in terms of its market success. To accomplish these research aims, six steps were carried out: (1) selection of globally accepted facilities for being successful, (2) analysis of precedents for the discovery of repeating servicescape design patterns, (3) knowledge acquisition and organization for each design patterns, (4) formulation of servicescape rules using the acquired and organized knowledge, (5) integration of the rules into a general design process of a facility as a system, and (6) application of the system in practice. The resulting system was presented to an expert in the field of theme park designs to confirm whether the design process is applicable and how it will perform in practice. From this interview, we received positive feedbacks and well as feedbacks for improvements in the aspects of the system's applicability in practice, its functionality, and usability. After confirming the applicability of the overall process of the system, we conducted an experiment to experts in practice from various design and planning fields and asked to go through two sets of scenarios in which the first is to design a given site without the system and the second is to design the same site with the system. After each scenario, the subjects were asked to fill out a revised After-Scenario Questionnaire (ASQ). From this experiment, the results indicate that the subjects felt an increase in their credence toward their designs in terms of its market success while the satisfaction with the easiness and the time it took decreased. If our system is revised in the aspects of usability and functionality, our system which uses precedent design patterns could be used to help small company designers to produce servicescape concept designs with more design credence.
Digital games are generating various types of virtual landscape and the importance of virtual lan... more Digital games are generating various types of virtual landscape and the importance of virtual landscape has been arises. However, there has not been any research done how to design the virtual landscape. To establish virtual landscape design methodology, establishing the classification system and suggesting the representative type of virtual landscape is needed. With this research, I collected the classification standard and established five standards; story, cooperation, interaction level, dimensions and shape of the space. With that system, I classified digital game and could prove the effectiveness. Also by classifying cases through 20 years of timeline, I could come out with three representative types. This result will work as a reference to the future research; establishing design methodology on virtual landscape.
Design experience from previous design cases could help designers solving current design problems... more Design experience from previous design cases could help designers solving current design problems. Therefore, a case-based recommender system can recall suitable design cases for designers based on a similarity measurement mechanism. In the context of Product-Service System (PSS) design, the measurement of similarity between different cases becomes more challenging because of the complex nature of the PSS design. In this research, we propose a similarity measurement framework of PSS design cases based on the context-based activity model. In the proposed framework, a PSS design case is indexed and quantified by design activity element, design process, and function requirement. Ways to measure similarity between design indexes and design cases are also specified. A case study along with an empirical validation was conducted to validate the framework.
Bio-inspired design was introduced as an alternative method to encourage breakthrough innovations... more Bio-inspired design was introduced as an alternative method to encourage breakthrough innovations during design projects by stimulating analogical reasoning and thinking of designers. However, the method did not perform as well as researchers expected because most designers, who are novices in the fields of biology and ecology, cannot infer the proper analogue (i.e. biological system) from nature. To resolve this fundamental problem, a causal model based representation framework for 'analogical reasoning' – searching and selecting the biological systems to apply – have been developed. In addition, ontology based repository structures and retrieval systems have been proposed to support 'analogical thinking' of designers. Nevertheless, these systematic approaches still restrict the candidates and inevitably lose potential biological systems relevant to the design project, due to the 'physical relation' biased problem and the ambiguity of the indexing mechanism of both current representation frameworks and retrieval systems. For example, the causality based support system known as a robust representation framework for a single biological system, stores information of a biological system only by its internal 'physical relations' and retrieves biological systetabms only by the physical relevance. However, from the perspective of ecological thinking, the further relatedness of 'physical, biological, and ecological relations' composes the holistic concept used to identify an organism in the flow of evolution because the 'biological and ecological relations' are also involved in the traits that designers may be interested in. Therefore, the supplementary information for 'biological and ecological relations' must be added to index the biological and environmental interactions, and to use the connectivity among entire organisms in the retrieval process. In this research, a causality based holistic representation framework for biological systems and an 'all-connected' ontology based repository and retrieval system are developed as a knowledge-based recommendation system to support bio-inspired design. The knowledge-based system we developed allows engineering designers to search and select a particular biological system and extract design strategy without much biological knowledge. This effort provides more opportunities in a bio-inspired design process by adding potential biological systems that might previously not have been considered.
This study proposes an advanced thermal control method that employs artificial neural network (AN... more This study proposes an advanced thermal control method that employs artificial neural network (ANN) models for predictive and adaptive thermal control. Two predictive and adaptive control logic approaches were proposed to simultaneously control indoor temperature and humidity as well as predicted mean vote (PMV) in a residential building. Their thermal performance was analysed and compared with that of non-ANN-based counterparts to evaluate architectural variables such as envelope insulation and building orientation. A numerical computer simulation method was used for the tests after demonstration of its validity based on comparison with results of field measurement. Analysis results revealed that the proposed predictive and adaptive control methods conditioned the indoor temperature, humidity and PMV effectively. The periods during which each thermal factor was in a comfortable range increased, and overshoots and undershoots out of the targeted comfortable ranges were reduced when using the ANN model. The results demonstrate the functionality of the proposed method for variation in architectural variables and that the ANN model has the potential to be successfully applied to building thermal controls.
Owing to the incredible increase in the amount of information on the World Wide Web, there is a s... more Owing to the incredible increase in the amount of information on the World Wide Web, there is a strong need for an efficient web page classification to retrieve useful information quickly. In this paper, we propose a novel simplified swarm optimization (SSO) to learn the best weights for every feature in the training dataset and adopt the best weights to classify the new web pages in the testing dataset. Moreover, the parameter settings play an important role in the update mechanism of the SSO so that we utilize a Taguchi method to determine the parameter settings. In order to demonstrate the effectiveness of the algorithm, we compare its performance with that of the well-known genetic algorithm (GA), Bayesian classifier, and K-nearest neighbor (KNN) classifiers according to four datasets. The experimental results indicate that the SSO yields better performance than the other three approaches.
Understanding how similar design appears is a key element to understanding companies’ design stra... more Understanding how similar design appears is a key element to understanding companies’ design strategies. However, it is difficult to evaluate companies’ design strategies with conventional style measurement methods since they only taxonomically measure whether a specific characteristic is included in a specific style. This study numerically measured car design similarities to synthesize and analyze car brand styles, thereupon discovering the design trends among car brands for strategic design positioning. This paper aims to find methods for quantifying style differences and identifying unique design elements of car designs among 23 automobile manufacturers based on design similarities of a large quantity of car designs (N = 119). To achieve this goal, a hybrid style quantification methodology – a mixture of Fourier decomposition, eye tracker, and shape grammar – was created to evaluate similarities, visual significance, and combinations of 19 car design elements. Fourier decomposition was incorporated to find the quantifiable values of design similarities of car design elements. Visual significance analysis was also conducted for each car design element through eye tracker to measure the importance of certain design elements for weighting factors. Then, each combination of design elements was compared with car design elements of other cars for similarity calculations. Finally, car design alternatives were synthesized, and transitions of design positioning were analyzed based on the similarity values weighed by the visual significance results. Using the suggested methods, alternate designs can be synthesized while preserving brands’ design styles, and design trends can be analyzed for strategic evaluation.
This study aims to develop and validate an annual photosensor performance simulation method (APPS... more This study aims to develop and validate an annual photosensor performance simulation method (APPSM) to compute the photosensor signals for a lighting control system under various daylight conditions. A series of computer simulations using PSENS, which is a simulation program within Radiance software were conducted and field measurements were performed under various daylight conditions in order to validate the simulation results of APPSM.
Results indicate that the photosensor signals predicted by PSENS and APPSM showed a strong linear correlation. Prediction results by APPSM generally consisted with the results field measurements, although slight differences between them existed under particular daylight conditions. The differences in photosensor signals between the prediction by APPSM and measurement effectively decreased as shielding conditions were applied to photosensors.
A strong linear relationship existed between the photosensor signals obtained from prediction by APPSM and the field measurements. The prediction models for the photosensor shielding conditions were acceptable with a significance level of 0.01. The majority of percent differences between the measured and simulated photosensor signals were within 10% under clear and partly cloudy sky conditions.
Virtual game controllers are essential for particular game genres where the game contents are tra... more Virtual game controllers are essential for particular game genres where the game contents are transplanted from various platforms into a smart-phone platform. Virtual images are projected as a game interface at the smartphone’s output screen. Therefore, a certain amount of space needs to be abandoned for the controller’s interface projection. In addition, the functions of the game contents are fundamentally limited, thus eliciting the necessity of a limited number of buttons. In this study, diverse types of interaction that occur between the user and touch-screen were researched, and adequate interactions for smart-phone game contents were extracted and analyzed. In addition, the focus is placed on minimizing the number of controller buttons while including diverse functions at the contents level. Notably, the study pointed out that previous virtual game controllers are a mere metaphor of traditional methods, thus limited to Tap interaction. By analyzing fighting action game contents, the Tap interaction is enhanced by adding Flick and Multi-touch interaction to diversify and enhance previous interaction values. Finally, a prototype was developed by ameliorating past interfaces and referring to the intrinsic features of the aforementioned types of interaction, followed by user evaluation. A previous questionnaire method was adjusted to the particular research purpose, and quantitative evaluation was conducted while documenting and analyzing the user-log data of repetitive experiments.
The results show that Flick and Multi-touch interaction techniques are beneficial under a smartphone touchscreen environment beyond the traditional Tap-only. Furthermore, functions are maintained with a minimum number of buttons while the situation compatibility of user interaction is verified. This study also shows that adding diverse types of interaction to the simple Tap-only affords a distinctive user experience of long-term interest and fun to the players that were previously restricted to the accustomed Tap-only. The results authenticate the applicability of the intrinsic fun mechanism to the smartphone based touchscreen game interaction. The study has implications in enhancing the traditional Tap-only based virtual game controller, which is a mere metaphor of controllers loaded onto other platforms, through proposing a tailored interface design and evaluation method under a smartphone platform. Furthermore, this study contributes objective reference source for the engineers to design future game contents, interface and heuristics evaluation in the platform.
Biomimetic design performed to develop a solution-shape has been offered as a successful approach... more Biomimetic design performed to develop a solution-shape has been offered as a successful approach for overcoming the limitations of typical design methods. Especially for the nose-shape of high-speed trains, the morphological characteristics of a superior bio-model were used in the design process. However, current design methods using the biomimetic approach, particularly in the morphological domain, do not support a technique to evaluate how close the new solution is to the optimal one; nor do they support alternative methodologies used to validate and verify the solution-shape being developed. Solution optimization in a biomimetic design means not only preserving the original shape of a bio-model but also validating and verifying it. Shape optimization for a design problem should accompany shape evaluation and modification conducted according to criteria involving both evolutionary traits and technological constraints. In this research we suggest a method to verify the original shape, and to validate the solution, using theoretical backgrounds from both systematic biology and evolutionary biology. In this paper, the morphological characteristics of a bio-model are verified and modified using a quantitative method. To validate the solution developed, new criteria are applied for high-speed-train design.
This study proposes an effective thermal control method for thermally comfortable and energy-effi... more This study proposes an effective thermal control method for thermally comfortable and energy-efficient environments in buildings with double skin envelopes. Four rule-based control logics and an artificial neural network (ANN)-based control logic were developed for the integrated control of openings and cooling systems in summer. Using numerical computer simulations, the performance of the proposed control logics was comparatively tested in terms of thermal performance and energy efficiency.
Analysis results imply that the more detailed rules of thermal control logic were effective to maintain the indoor temperature conditions within comfortable ranges. The ANN-based predictive and adaptive control logic presented its potential as an advanced temperature control method with an increased temperature comfort period, decreased standard deviation of temperature from the center of the comfortable range, and decreased number and ratio of overshoots and undershoots out of the comfort range. The additional rules embedded for control logic or ANN applications yielded a more comfortable temperature environment in an integrated manner according to the properly designed operations of envelope openings and the cooling system. However, logics with additional rules and ANN models consumed more energy for space cooling. Therefore, the rule-based controls with advanced logics or an ANN model are required in case occupant comfort is a primary factor to be satisfied. In other cases, the simple rule-based logic is effectively applied.
This study describes integrated logic for an artificial neural network (ANN) to control heating d... more This study describes integrated logic for an artificial neural network (ANN) to control heating devices on a continuous basis. Two ANN-based control logic systems and two conventional rule-based logic systems were developed to control a heating device and the openings of a double skin enveloped building. The ANN-based logic controls heating devices on a continuous basis according to the indoor temperature. The rule-based logic controls heating systems and openings at envelopes in two-position on/off operation. Control performance for the developed logic was numerically conducted using computer simulations for a small office space with double skin envelopes during the heating season.
Analysis results indicate that the ANN-based temperature control logic resulted in a more stable temperature near the center of the comfortable range with a reduced opening period of the internal envelope. The reduced number of on/off moments of the heating device and the openings in the ANN-based logic were predicted to save energy and prevent system degradation. The use of ANN-based logic would be effective for maintaining a stable thermal environment and for system operation. Rule-based logic can be effectively used to improve building energy efficiency. In this study, two ANN-based logic types were developed for heating devices controlled on a continuous basis and their performance was compared with those of rule-based on/off logic. Thus, in order to cover the limitation of this study, further study is warranted for examining the clear difference achieved by ANN-based vs. rule-based control, when they are applied to control heating output on a continuous basis.
This study aims at developing an indoor temperature control method that could provide comfortable... more This study aims at developing an indoor temperature control method that could provide comfortable thermal conditions by integrating heating system control and the opening conditions of building envelopes. Artificial neural network (ANN)-based temperature control logic was developed for the control of heating systems and openings at the building envelopes in a predictive and adaptive manner. Numerical comparative performance tests for the ANN-based temperature control logic and conventional non-ANN-based counterpart were conducted for single skin enveloped and double skin enveloped buildings after the simulation program was validated by comparing the simulation and the field measurement results. Analysis results revealed that the ANN-based control logic improved the indoor temperature environment with an increased comfortable temperature period and decreased overshoot and undershoot of temperatures outside of the operating range. The proposed logic did not show significant superiority in energy efficiency over the conventional logic. The ANN-based temperature control logic was able to maintain the indoor temperature more comfortably and with more stability within the operating range due to the predictive and adaptive features of ANN models.
Most of the assessment of creativity in product design is based on the outcome, not the design pr... more Most of the assessment of creativity in product design is based on the outcome, not the design process from which the creative ideas are derived. In this paper, we revealed the correlation coefficient of 20 factors critical in the product design process and the quality of design creativity via investigation of the design processes and outcomes of 30 senior student designers. Six closely related factors were identified as variables to calculate the design creativity. An assessment formula was proposed: the corresponding correlation coefficient is the weight factor of each variable, and the sum represents the design creativity degree. Our quantitative approach can improve the validity and reliability of assessment of creativity in product design.
The combined effects of color temperature and illuminance in a small office on visual response an... more The combined effects of color temperature and illuminance in a small office on visual response and mood under various lighting conditions were examined in this study. Visual annoyance tests were conducted using a sample of 20 subjects in a full-scale mock-up test space. Computer and paper-based reading tasks were conducted for 500 lx and 750 lx illuminance levels under 3,000 K, 4,000 K and 6,500 K conditions. Two hypotheses were considered for the test in this study. The primary hypothesis was that visual perception is affected by the color temperatures of light sources. The secondary hypothesis was that better moods, such as relaxed and cozy feelings, are associated with low color temperatures given equal illuminance levels. The visual environment under the 3,000 K condition was characterized by glare and brightness, resulting in visual discomfort when target illuminance was higher than 500 lx. Occupants preferred 500 lx under the 6,500 K condition, and 500 lx and 750 lx under the 4,000 K condition, reporting better visual satisfaction when performing office tasks. Prediction models for visual comfort suggest that the less that subjects are visually bothered by light during tasks, the more visual comfort they feel. User satisfaction with light source color is critical for the prediction of visual comfort under different lighting conditions. Visual comfort was the most influential factor on mood. Lower color temperature was associated with better mood at lower illuminance levels, while higher color temperature was preferred at higher illuminance levels.
The influences of lighting conditions, which is combined by color temperature and lighting types,... more The influences of lighting conditions, which is combined by color temperature and lighting types, on visual responses are discussed in this study. Visual annoyance tests were performed in a full-scale mock-up test space, which was prepared for a small private office environment. Lamps with color temperature of 3,500 K and 5,000 K were applied to a direct lighting type and direct/indirect lighting type. Results indicate that overall glare sensation for computer-based task was stronger than that of paper-based task. Color temperature of 3,500 K applied to a direct lighting type caused the worst glare. Overall, visual discomfort were not reported under all lighting conditions. The direct/indirect lighting type succeeded to ensure better comfort compared to the direct lighting type. The number of letters which were typed in showed no significant difference under all lighting conditions. In order to enhance good quality of lighting condition, the direct lighting type should ensure good color rendering, reduction of glare and prevention of tensed sensation. The direct/indirect lighting type condition should keep the space and desktop surface bright.
This study aims to develop Artificial Neural Network (ANN) models to examine the thermal performa... more This study aims to develop Artificial Neural Network (ANN) models to examine the thermal performance of double skin-enveloped buildings under different opening conditions. Performance tests of the ANN models, which were developed for integrated temperature control logics, were conducted for a space with a double skin envelope in a one-storey building during the winter.
ANN models were embedded in the logic for predictive and adaptive controls in order to ensure comfortable, energy-efficient indoor temperature conditions. Four ANN models were developed to predict future indoor temperatures under different opening conditions of the internal and external envelopes. Their performances were preliminarily tested by comparing them with conventional non-ANN-based methods in terms of thermal control and energy efficiency.
The comparative analysis revealed that the ANN models were properly organized to predict future indoor temperature conditions. Based on the prediction accuracy, the optimal opening conditions and heating system operations could be determined to guarantee advanced methods for effective thermal control and energy efficiency. Thus, ANN models are expected to be applied to the temperature control logic for double skin-enveloped buildings in order to improve their thermal control performance and energy efficiency.
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Papers by Ji-Hyun Lee
Results indicate that the photosensor signals predicted by PSENS and APPSM showed a strong linear correlation. Prediction results by APPSM generally consisted with the results field measurements, although slight differences between them existed under particular daylight conditions. The differences in photosensor signals between the prediction by APPSM and measurement effectively decreased as shielding conditions were applied to photosensors.
A strong linear relationship existed between the photosensor signals obtained from prediction by APPSM and the field measurements. The prediction models for the photosensor shielding conditions were acceptable with a significance level of 0.01. The majority of percent differences between the measured and simulated photosensor signals were within 10% under clear and partly cloudy sky conditions.
The results show that Flick and Multi-touch interaction techniques are beneficial under a smartphone touchscreen environment beyond the traditional Tap-only. Furthermore, functions are maintained with a minimum number of buttons while the situation compatibility of user interaction is verified. This study also shows that adding diverse types of interaction to the simple Tap-only affords a distinctive user experience of long-term interest and fun to the players that were previously restricted to the accustomed Tap-only. The results authenticate the applicability of the intrinsic fun mechanism to the smartphone based touchscreen game interaction. The study has implications in enhancing the traditional Tap-only based virtual game controller, which is a mere metaphor of controllers loaded onto other platforms, through proposing a tailored interface design and evaluation method under a smartphone platform. Furthermore, this study contributes objective reference source for the engineers to design future game contents, interface and heuristics evaluation in the platform.
Analysis results imply that the more detailed rules of thermal control logic were effective to maintain the indoor temperature conditions within comfortable ranges. The ANN-based predictive and adaptive control logic presented its potential as an advanced temperature control method with an increased temperature comfort period, decreased standard deviation of temperature from the center of the comfortable range, and decreased number and ratio of overshoots and undershoots out of the comfort range. The additional rules embedded for control logic or ANN applications yielded a more comfortable temperature environment in an integrated manner according to the properly designed operations of envelope openings and the cooling system. However, logics with additional rules and ANN models consumed more energy for space cooling. Therefore, the rule-based controls with advanced logics or an ANN model are required in case occupant comfort is a primary factor to be satisfied. In other cases, the simple rule-based logic is effectively applied.
Analysis results indicate that the ANN-based temperature control logic resulted in a more stable temperature near the center of the comfortable range with a reduced opening period of the internal envelope. The reduced number of on/off moments of the heating device and the openings in the ANN-based logic were predicted to save energy and prevent system degradation. The use of ANN-based logic would be effective for maintaining a stable thermal environment and for system operation. Rule-based logic can be effectively used to improve building energy efficiency. In this study, two ANN-based logic types were developed for heating devices controlled on a continuous basis and their performance was compared with those of rule-based on/off logic. Thus, in order to cover the limitation of this study, further study is warranted for examining the clear difference achieved by ANN-based vs. rule-based control, when they are applied to control heating output on a continuous basis.
ANN models were embedded in the logic for predictive and adaptive controls in order to ensure comfortable, energy-efficient indoor temperature conditions. Four ANN models were developed to predict future indoor temperatures under different opening conditions of the internal and external envelopes. Their performances were preliminarily tested by comparing them with conventional non-ANN-based methods in terms of thermal control and energy efficiency.
The comparative analysis revealed that the ANN models were properly organized to predict future indoor temperature conditions. Based on the prediction accuracy, the optimal opening conditions and heating system operations could be determined to guarantee advanced methods for effective thermal control and energy efficiency. Thus, ANN models are expected to be applied to the temperature control logic for double skin-enveloped buildings in order to improve their thermal control performance and energy efficiency.
Results indicate that the photosensor signals predicted by PSENS and APPSM showed a strong linear correlation. Prediction results by APPSM generally consisted with the results field measurements, although slight differences between them existed under particular daylight conditions. The differences in photosensor signals between the prediction by APPSM and measurement effectively decreased as shielding conditions were applied to photosensors.
A strong linear relationship existed between the photosensor signals obtained from prediction by APPSM and the field measurements. The prediction models for the photosensor shielding conditions were acceptable with a significance level of 0.01. The majority of percent differences between the measured and simulated photosensor signals were within 10% under clear and partly cloudy sky conditions.
The results show that Flick and Multi-touch interaction techniques are beneficial under a smartphone touchscreen environment beyond the traditional Tap-only. Furthermore, functions are maintained with a minimum number of buttons while the situation compatibility of user interaction is verified. This study also shows that adding diverse types of interaction to the simple Tap-only affords a distinctive user experience of long-term interest and fun to the players that were previously restricted to the accustomed Tap-only. The results authenticate the applicability of the intrinsic fun mechanism to the smartphone based touchscreen game interaction. The study has implications in enhancing the traditional Tap-only based virtual game controller, which is a mere metaphor of controllers loaded onto other platforms, through proposing a tailored interface design and evaluation method under a smartphone platform. Furthermore, this study contributes objective reference source for the engineers to design future game contents, interface and heuristics evaluation in the platform.
Analysis results imply that the more detailed rules of thermal control logic were effective to maintain the indoor temperature conditions within comfortable ranges. The ANN-based predictive and adaptive control logic presented its potential as an advanced temperature control method with an increased temperature comfort period, decreased standard deviation of temperature from the center of the comfortable range, and decreased number and ratio of overshoots and undershoots out of the comfort range. The additional rules embedded for control logic or ANN applications yielded a more comfortable temperature environment in an integrated manner according to the properly designed operations of envelope openings and the cooling system. However, logics with additional rules and ANN models consumed more energy for space cooling. Therefore, the rule-based controls with advanced logics or an ANN model are required in case occupant comfort is a primary factor to be satisfied. In other cases, the simple rule-based logic is effectively applied.
Analysis results indicate that the ANN-based temperature control logic resulted in a more stable temperature near the center of the comfortable range with a reduced opening period of the internal envelope. The reduced number of on/off moments of the heating device and the openings in the ANN-based logic were predicted to save energy and prevent system degradation. The use of ANN-based logic would be effective for maintaining a stable thermal environment and for system operation. Rule-based logic can be effectively used to improve building energy efficiency. In this study, two ANN-based logic types were developed for heating devices controlled on a continuous basis and their performance was compared with those of rule-based on/off logic. Thus, in order to cover the limitation of this study, further study is warranted for examining the clear difference achieved by ANN-based vs. rule-based control, when they are applied to control heating output on a continuous basis.
ANN models were embedded in the logic for predictive and adaptive controls in order to ensure comfortable, energy-efficient indoor temperature conditions. Four ANN models were developed to predict future indoor temperatures under different opening conditions of the internal and external envelopes. Their performances were preliminarily tested by comparing them with conventional non-ANN-based methods in terms of thermal control and energy efficiency.
The comparative analysis revealed that the ANN models were properly organized to predict future indoor temperature conditions. Based on the prediction accuracy, the optimal opening conditions and heating system operations could be determined to guarantee advanced methods for effective thermal control and energy efficiency. Thus, ANN models are expected to be applied to the temperature control logic for double skin-enveloped buildings in order to improve their thermal control performance and energy efficiency.