Nowadays, rapid developments of Internet of Things (IoT) technologies have increased possibilities of realizing smart cities where collaborations and integrations of various IoT application systems are essential. However, IoT application... more
Nowadays, rapid developments of Internet of Things (IoT) technologies have increased possibilities of realizing smart cities where collaborations and integrations of various IoT application systems are essential. However, IoT application systems have often been designed and deployed independently without considering the standards of devices, logics, and data communications. In this paper, we present the design and implementation of the IoT server platform called Smart Environmental Monitoring and Analytical in Real-Time (SEMAR) for integrating IoT application systems using standards. SEMAR offers Big Data environments with built-in functions for data aggregations, synchronizations, and classifications with machine learning. Moreover, plug-in functions can be easily implemented. Data from devices for different sensors can be accepted directly and through network connections, which will be used in real-time for user interfaces, text files, and access to other systems through Represent...
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Nowadays, human indoor localization services inside buildings or on underground streets are in strong demand for various location-based services. Since conventional GPS cannot be used, indoor localization systems using wireless... more
Nowadays, human indoor localization services inside buildings or on underground streets are in strong demand for various location-based services. Since conventional GPS cannot be used, indoor localization systems using wireless technologies have been extensively studied. Previously, we studied a fingerprint-based indoor localization system using IEEE802.15.4 devices, called FILS15.4, to allow use of inexpensive, tiny, and long-life transmitters. However, due to the narrow channel band and the low transmission power, the link quality indicator (LQI) used for fingerprints easily fluctuates by human movements and other uncontrollable factors. To improve the localization accuracy, FILS15.4 restricts the detection granularity to one room in the field, and adopts multiple fingerprints for one room, considering fluctuated signals, where their values must be properly adjusted. In this paper, we present a fingerprint optimization method for finding the proper fingerprint parameters in FILS15...
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Nowadays, indoor localization systems using IEEE 802.11 have been actively explored for location-based services, since GPS cannot identify floors or rooms in buildings. However, the user-side device is usually large and consumes high... more
Nowadays, indoor localization systems using IEEE 802.11 have been actively explored for location-based services, since GPS cannot identify floors or rooms in buildings. However, the user-side device is usually large and consumes high energy. In this paper, the authors propose a fingerprint-based indoor localization system using IEEE 802.15.4 that allows the use of a small device with a long-life battery, named FILS15.4. A user carries a small transmitter whose signal is received by multiple receivers simultaneously. The received signal strengths are compared with the fingerprints to find the current location. To address signal fluctuations caused by the low-power narrow-band signal, FILS15.4 limits one room as the localization unit, prepares plural fingerprints for each room, and allocates a sufficient number of receivers in the field. For evaluations, extensive experiments were conducted at #2 Engineering Building in Okayama University and confirmed high detection accuracy with suf...
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The increasing popularity of indoor localization systems brings the need of providing energy and cost-efficient service. Currently, we are developing the fingerprint-based indoor localization system using IEEE 802.15.4 named FILS15.4. It... more
The increasing popularity of indoor localization systems brings the need of providing energy and cost-efficient service. Currently, we are developing the fingerprint-based indoor localization system using IEEE 802.15.4 named FILS15.4. It uses a small transmitter powered by a coin battery, limits the detection resolution by one room, allocates several receivers on the field, and assigns multiple fingerprints using the parameter optimization method. It has been evaluated only for one-floor environments. This paper investigates the applicability of FILS15.4 in a two-floors environment of the #2 Engineering Building in Okayama University. The receivers allocated on both floors are used together for localization. The experiment results confirm sufficient detection accuracy.
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Our society now has driven us into an era where almost everything can be digitally monitored and controlled including the human body. The growth of wireless body area network (WBAN), as a specific scope of sensor networks which mounted or... more
Our society now has driven us into an era where almost everything can be digitally monitored and controlled including the human body. The growth of wireless body area network (WBAN), as a specific scope of sensor networks which mounted or attached to human body also developing rapidly. It allows people to monitor their health and several daily activities. This study is intended to review the trend of WBAN especially on Android, one of the most popular smartphone platforms. A systematic literature review is concerned to the following parameters: the purpose of the device and/or application, the type of sensors, the type of Android device, and its connectivity. Most of the studies were more concern to healthcare or medical monitoring systems: blood pressure, electro cardiograph, tremor detection, etc. On the other hand, the rest of them aimed for activity tracker, environment sensing, and epidemic control. After all, those studies shown that not only Android can be a powerful platform to process data from various sensors but also smartphones can be a good alternative to develop WBANs for medical and other daily applications.
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Previously, we have studied the fingerprint-based indoor localization system using IEEE 802.15.4 wireless devices as low-power and compact ones suitable for continuous possessions of the users. For its practical applications, this... more
Previously, we have studied the fingerprint-based indoor localization system using IEEE 802.15.4 wireless devices as low-power and compact ones suitable for continuous possessions of the users. For its practical applications, this FILS15.4 limits the detection resolution to one room in the target field. Unfortunately, human movements often cause the fluctuation of the receiving signal strength by affecting wireless propagation dynamics, which decreases the room detection accuracy of FILS15.4. To overcome the problem, in this paper, we investigate the detection accuracy improvement of FILS15.4, when the number of allocated receivers is increased in the field, and the number of fingerprints is increased for each room where the proper values are selected using the parameter optimization method. For the evaluation, we conducted extensive experiments using the FILS15.4 testbed system with three to five receivers at two floors of #2 Engineering Building in Okayama University. The results show that the use of five receivers achieves the accuracy up to 99.71% on average, whereas the use of three or four receivers does 82.64% and 97.37% respectively.
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Football as the most popular and most interesting sport in the world has applied the technology to obtain more match data easily. Data analysis in football matches can be used to find out how the match is going and even to predict the... more
Football as the most popular and most interesting sport in the world has applied the technology to obtain more match data easily. Data analysis in football matches can be used to find out how the match is going and even to predict the winner of a match. This paper proposes the Analytical Hierarchy Process (AHP) method to predict the winners of soccer matches that can finally predict the champion of a tournament. For one team, six factors and 13 alternative values are applied to AHP method to get the final score that can be compared to the opponent’s final score in a match. To evaluate the proposal, matches in UEFA Champions League 2018 are simulated. Based on the results, the method can give correct predictions on 13 matches, which means the effectiveness of the applied method is 86.67%. The team with the highest final score can be predicted as the champion of the tournament.
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Many Electrocardiogram (ECG) signal researches utilize MIT-BIH Arrhythmia database (MITDB) for offline testing in simulation only. On the other side, real-time ECG hardware testing requires a patient simulator for generating ECG signal... more
Many Electrocardiogram (ECG) signal researches utilize MIT-BIH Arrhythmia database (MITDB) for offline testing in simulation only. On the other side, real-time ECG hardware testing requires a patient simulator for generating ECG signal with abnormalities. This research aims to create a bridge between simulation and hardware testing for ECG researches. Taking advantages of Simulink support package for Arduino, an ECG waveform generator is designed with minimum hardware. Using simple R-2R ladder D/A converter, this waveform generator can produce ECG records partially from physionet with high sampling precision and good linearity. Moreover, with simulation approach, the raw ECG waveform can be modified and generated directly from Simulink at ease.
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Nowadays, indoor positioning systems (IPS) have gained popularity for offering location-based services. Previously, we have proposed the fingerprint-based indoor positioning system using IEEE 802.15.4. By limiting the positioning... more
Nowadays, indoor positioning systems (IPS) have gained popularity for offering location-based services. Previously, we have proposed the fingerprint-based indoor positioning system using IEEE 802.15.4. By limiting the positioning resolution by one room, it can detect the current position accurately. However, this detection was only performed at one time, thus the accuracy has not been observed. In this paper, we present experimental evaluations of the implemented system when it runs for a long time on two floors with 15 rooms of #2 Engineering Building in Okayama University. The results show that it achieves 93.41% and 91.83% average accuracy of the correct room detection on each floor.
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To achieve the high accuracy while wearing an inexpensive, tiny, and long-life transmitter, we have developed a fingerprint-based indoor localization system. It adopts IEEE802.15.4 devices and restricts the detection granularity to one... more
To achieve the high accuracy while wearing an inexpensive, tiny, and long-life transmitter, we have developed a fingerprint-based indoor localization system. It adopts IEEE802.15.4 devices and restricts the detection granularity to one room in an indoor environment. Unfortunately, wireless signals of the devices often fluctuate due to human movements and other uncontrollable factors. It has been observed that it can be solved by assigning plural fingerprints to one room. However, their values need to be properly selected. In this paper, we study the parameter optimization method for this indoor localization system. An existing parameter optimization tool is employed where the score function is newly defined to estimate the optimality of the current parameters. For evaluations, we apply the method to the measured data using the system in #2 Engineering Building of Okayama University. The results show that the detection accuracy becomes higher than 95% for any room by increasing the number of fingerprints and optimizing the parameter values by the proposal.
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Short-range, wireless communications in the vicinity of, or inside, a human body (but not limited to humans) are specified in this standard. It uses existing industrial scientific medical (ISM) bands as well as frequency bands approved by... more
Short-range, wireless communications in the vicinity of, or inside, a human body (but not limited to humans) are specified in this standard. It uses existing industrial scientific medical (ISM) bands as well as frequency bands approved by national medical and/or regulatory authorities. These sensors provide accurate and reliable information about the situation or activity occurring at any time. This high responsiveness of these sensors has made lives easy and safe. This article will perform an investigation on the WBAN's application for motion detection based on android smartwatch. The main problem is how to the sensors that attached on the human body can send of data via Bluetooth and read the motion and orientation of the body and display in the graph form. However, if the sensors do not match, the result of output display inappropriate. This article proposed method by using accelerometer and gyroscope sensors which are integrated with smartwatch to overcome the main problem. ...
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Abstrak – Dunia digital kini telah sampai pada era di mana begitu banyak unsur fisik dapat terhubung dandimonitor secara jarak jauh dengan penggunaan sensor yang terhubung dalam suatu jaringan komunikasinirkabel yang berbasis internet... more
Abstrak – Dunia digital kini telah sampai pada era di mana begitu banyak unsur fisik dapat terhubung dandimonitor secara jarak jauh dengan penggunaan sensor yang terhubung dalam suatu jaringan komunikasinirkabel yang berbasis internet (internet of things). Pelayanan kesehatan juga tak luput dari sorotanpenggunaan IoT terutama dengan meningkatnya berbagai isu penyakit kronis yang dapat menurunkanharapan hidup manusia. Jaringan yang secara khusus menggunakan berbagai sensor yang ditempatkan padatubuh manusia ini disebut wireless body area network (WBAN). Artikel ini mengulas tentang bagaimanaperkembangan WBAN dalam menjawab berbagai kebutuhan peningkatan layanan kesehatan secarakomprehensif dan kontinyu tanpa terhalang keterbatasan jarak dan waktu antara pasien dengan paramedis.Teknologi pemantauan kesehatan yang bersifat mobile (m-Health) terus dikembangkan demi meningkatkanefektivitas dan efisiensi layanan kesehatan. Berbagai isu dan tantangan juga dikemukakan sehingga dapatmenjadi ...
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Sistem komunikasi taktis merupakan sistem komunikasi yang diterapkan dalam suatu operasi militer dengan kriteria yang lebih ketat daripada komunikasi komersial. Salah satu kriteria yang sangat penting adalah faktor keamanan. Komunikasi... more
Sistem komunikasi taktis merupakan sistem komunikasi yang diterapkan dalam suatu operasi militer dengan kriteria yang lebih ketat daripada komunikasi komersial. Salah satu kriteria yang sangat penting adalah faktor keamanan. Komunikasi ini sangat rentan terhadap gangguan berupa jamming yang dibangkitkan oleh musuh untuk mengganggu kelancaran pertukaran informasi. Faktor lain yang sangat penting adalah fleksibilitas jaringan dalam mengatasi mobilitas yang tinggi dan pengiriman data dalam orde besar. Hal tersebut dapat diatasi dengan skema modulasi/multiplexing OFDM. Untuk memenuhi kriteria khusus dari komunikasi taktis, sistem OFDM tersebut dilengkapi dengan pengkodean kanal dan interleaving untuk mengatasi kerusakan informasi akibat adanya jamming. Pada penelitian ini akan dilakukan evaluasi terhadap kinerja sistem OFDM jika ditambah Convolutional Encoder dan Interleaver. Strategi jamming yang diterapkan adalah singletone dan multitone jamming. Gangguan ini menyerang pada saat sinyal informasi melewati kanal AWGN. Berdasarkan hasil yang dicapai, convolutional coding dengan rate 1 2 dipilih sebagai encoder, karena BER yang didapatkan lebih kecil daripada rate 2 3. Sementara itu, pada pengujian skema interleaver, diperoleh hasil bahwa helical-scan interleaver lebih unggul daripada block interleaver maupun random interleaver. Pada nilai Eb/N0 yang sama, helical-scan interleaver dapat mencapai BER paling kecil, kemudian disusul block interleaver dan random interleaver. Pada parameter interleaving gain, block interleaver memberikan gain sebesar 1dB saat sistem diserang singletone jamming dan 1,85 dB saat sistem diserang multitone jamming jika dibandingkan dengan random interleaver. Sedangkan dengan helical-scan interleaver didapatkan gain 1,2 dB dan 1,9 dB untuk singletone dan multitone jamming. Namun karena kendala pengaplikasian, dimana helical-scan interleaver memerlukan matriks sementara yang nilainya harus sama dengan jumlah bit informasi yang dikirim, maka penggunaan block interleaver lebih direkomendasikan dalam sistem komunikasi taktis.
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Tactical communications is a communication system which is applied to a military operation with some strict requirements compared to a commercial communication system. One of the important requirement is its security. This communication... more
Tactical communications is a communication system which is applied to a military operation with some strict requirements compared to a commercial communication system. One of the important requirement is its security. This communication has a high risk to be attacked by jamming which generated by the adversary. The other important requirement is network flexibility to handle its high mobility and information exchange in a big order. To fulfil those special requirement of tactical communication, OFDM system is equipped with channel coding and interleaving to handle information damage caused by jamming. The jamming strategy used in this research is single-tone and multitone jamming which strike while information signal pass the AWGN channel. In this research. evaluate the performance of OFDM system which is equipped with Convolutional Encoder and Interleaver with various schemes. By using a half-rate convolutional encoder, for both parameters BER and interleaving gain, helical-scan interleaver scheme shows the best performance among block and random interleaver. However due to its complexity in applying this scheme, block interleaver which is the second best is preferred.