Johann Hurink
University of Twente, Applied Mathematics, Faculty Member
- I am a full professor at the Department of Applied Mathematics at the University of Twente and since 2020 also the D... moreI am a full professor at the Department of Applied Mathematics at the University of Twente and since 2020 also the Director of the 4TU Applied Mathematics Institute in the Netherlands. I am involved in many European and national research projects in the area of optimization and control problems for energy management and smart grids.edit
Research Interests:
Research Interests:
Research Interests:
Research Interests:
A unit disk graph is the intersection graph of unit disks in the euclidean plane. We present a polynomial-time approximation scheme for the maximum weight independent set problem in unit disk graphs. In contrast to previously known... more
A unit disk graph is the intersection graph of unit disks in the euclidean plane. We present a polynomial-time approximation scheme for the maximum weight independent set problem in unit disk graphs. In contrast to previously known approximation schemes, our approach does not require a geometric representation (specifying the coordinates of the disk centers). The approximation algorithm presented is robust in the sense that it accepts any graph as input and either returns a (1+)-approximate independent set or a certificate showing that the input graph is no unit disk graph. The algorithm can easily be extended to other families of intersection graphs of geometric objects.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Applied Mathematics, Computer Science, Physics, Chemistry, Project Management, and 13 moreOperations Research, Management Science, Scheduling, Project manager, Project Planning, Cor, Granular Matter, Project Scheduling, Numerical Analysis and Computational Mathematics, Chemical Engineering Science, Integer Program, Disaster Recovery Using Operations Research and Management Science, and Decomposition method
Research Interests:
This paper presents a real-time monitoring and control system for low voltage grids built with Smart State Technology's (SST) LV-Sensors and their open platform together with the TRIANA energy management methodology. This platform... more
This paper presents a real-time monitoring and control system for low voltage grids built with Smart State Technology's (SST) LV-Sensors and their open platform together with the TRIANA energy management methodology. This platform uses synchronized real-time measurement data from various locations in the grid. The presented control system uses this real-time data to resolve deviations in power consumption from a given planning. Based on this solution, necessary actions can be taken to avoid grid overloading and enhance the Quality of Service (QoS) to customers. The control system, implemented using DEMKit, runs on the SST LV-Sensors modules. Initial integration tests show that the solution works stable and resolves prediction errors to ensure QoS.
Research Interests:
Using the flexibility of batteries and households, the overall stress on the network can be reduced, reinforcements to the grid can be postponed or even avoided, and losses can be minimized. However, the current pricing mechanisms do not... more
Using the flexibility of batteries and households, the overall stress on the network can be reduced, reinforcements to the grid can be postponed or even avoided, and losses can be minimized. However, the current pricing mechanisms do not stimulate to obtain these goals. Within the GridFlex Heeten project, we calculate and send these control signals to 24 household batteries and send incentive signals to households. Determining the control and incentive signals depends on the criteria we take for our optimization. Therefore, the entire network, including geographical layout is modelled and described in a simulation tool called DEMKit.
Research Interests:
In the future of Smart Grids, many different devices have to be integrated into one overall system. These devices are of various types, they are related to various forms of energy, they have to exchange these different forms of energy,... more
In the future of Smart Grids, many different devices have to be integrated into one overall system. These devices are of various types, they are related to various forms of energy, they have to exchange these different forms of energy, and together they have to work towards common objectives. To handle such a system, a general model is required, which allows the integration of all these different devices, energy forms and objectives and which is able to incorporate also future developments for which the concrete setting can not be foreseen yet. In this paper, we present such a flexible model which handles different types of devices and which supports arbitrary ways of energy flows between devices. Instead of considering complex operations of devices we introduce simple basic devices which can be easily combined to obtain advanced functionality. The flexibility of the resulting model is demonstrated by considering some advanced devices but also by giving a reduction between Binary Li...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
ABSTRACT
Research Interests:
Research Interests:
Research Interests:
ABSTRACT Due to increasing energy prices and the greenhouse effect, a more efficient energy supply is desirable, preferably based on renewable sources. To cope with the decrease of flexibility due to the introduction of renewables in... more
ABSTRACT Due to increasing energy prices and the greenhouse effect, a more efficient energy supply is desirable, preferably based on renewable sources. To cope with the decrease of flexibility due to the introduction of renewables in production side of the supply chain, a more flexible consumer side is required. In literature, a lot of management methodologies are proposed to exploit the flexibility of consuming devices. Due to the large number of devices, these methodologies are often based on cost functions. Comparing the results of different methodologies is hard since differences in results can be caused by the methodologies itself or by less good defined cost functions. In this paper an auction based realtime control is compared with an ILP based realtime control using identical cost functions. Furthermore, the influence of planning on these strategies is studied. The simulation results show that planning leads to better and more predictable results. Furthermore, planning is best combined with an auction. However, the auction should slightly be altered to decrease communication and to be able to cope with (local) grid constraints.
Research Interests:
â–º Modeling a scheduling problem arising in the energy supply chain to plan a fleet of microCHP appliances. â–º Developing a dynamic programming (DP) approach for the planning problem for a single house. â–º Developing an iterative... more
â–º Modeling a scheduling problem arising in the energy supply chain to plan a fleet of microCHP appliances. â–º Developing a dynamic programming (DP) approach for the planning problem for a single house. â–º Developing an iterative approach for the fleet scheduling problem based on the DP approach for the single house.
Research Interests:
Due to increasing energy prices and the greenhouse effect more efficient electricity production is desirable, referably based on renewable sources. In the last years, a lot of technologies have been developed to improve the efficiency of... more
Due to increasing energy prices and the greenhouse effect more efficient electricity production is desirable, referably based on renewable sources. In the last years, a lot of technologies have been developed to improve the efficiency of the electricity usage and supply. Next to large scale technologies such as windturbine parks, a lot of domestic technologies are developed. These domestic technologies
Research Interests:
Research Interests:
Off-grid houses can be considered an important concept to increase the access to electricity throughout the world. Although there are quite some initiatives in place to improve the access to electricity, the implementation rate of... more
Off-grid houses can be considered an important concept to increase the access to electricity throughout the world. Although there are quite some initiatives in place to improve the access to electricity, the implementation rate of practical solutions is far below the UN Sustainable Development Goal 7: Energy (SDG 7) + for 2030. This situation is most apparent in Sub-Saharan Africa, where the current trends of electricity access calculated by the World Bank indicate that this region will not be able to achieve the SDG 7 target. Another worldwide trend which may help to increase electricity access is that currently, a lot of renewable energy generation is realized locally in houses (especially Solar Photovoltaics (PV)). This paper reviews the recent developments to increase the access to electricity in the world and the implementation of off-grid houses in different scenarios. The focus here is on the different efforts to create off-grid houses considering their challenges on a macro ...
Research Interests:
The introduction of microCHP (Combined Heat and Power) appliances and other means of distributed generation causes a shift in the way electricity is produced and consumed. Households themselves produce electricity and deliver the surplus... more
The introduction of microCHP (Combined Heat and Power) appliances and other means of distributed generation causes a shift in the way electricity is produced and consumed. Households themselves produce electricity and deliver the surplus to the grid. In this way, the distributed generation also has implications on the transformers and, thus, on the grid. In this work we study the
Research Interests:
ABSTRACT Many multicore processors are capable of decreasing the voltage and clock frequency to save energy at the cost of an increased delay. While a large part of the theory oriented literature focuses on local dynamic voltage and... more
ABSTRACT Many multicore processors are capable of decreasing the voltage and clock frequency to save energy at the cost of an increased delay. While a large part of the theory oriented literature focuses on local dynamic voltage and frequency scaling (local DVFS), where every core’s voltage and clock frequency can be set separately, this article presents an in-depth theoretical study of the more commonly available global DVFS that makes such changes for the entire chip. This article shows how to choose the optimal clock frequencies that minimize the energy for global DVFS, and it discusses the relationship between scheduling and optimal global DVFS. Formulas are given to find this optimum under time constraints, including proofs thereof. The problem of simultaneously choosing clock frequencies and a schedule that together minimize the energy consumption is discussed, and based on this a scheduling criterion is derived that implicitly assigns frequencies and minimizes energy consumption. Furthermore, this article studies the effectivity of a large class of scheduling algorithms with regard to the derived criterion, and a bound on the maximal relative deviation is given. Simulations show that with our techniques an energy reduction of 30% can be achieved with respect to state-of-the-art research.
Research Interests:
ABSTRACT
Research Interests:
In this paper we study the following generalization of the job-shop scheduling problem. Each operation can be performed by one machine out of a set of machines given for this operation. The processing time does not depend on the machine... more
In this paper we study the following generalization of the job-shop scheduling problem. Each operation can be performed by one machine out of a set of machines given for this operation. The processing time does not depend on the machine which has been chosen ...
Research Interests:
Next-Generation Monitoring, Analysis, and Control for the Future Smart Control Center........ P. Zhang, F. Li, and N. Bhatt 186 Demand Response and Distribution Grid Operations: Opportunities and Challenges.... J. Medina, N. Muller, and I. Roytelman 193 A Hybrid Smart AC/DC Power System.............more