• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.2
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• pp.149-156
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• 2012

Support vector machines (SVMs) are well known for their pattern recognition capability, but proper care should be taken to alleviate their inherent implementation cost resulting from high computational intensity and memory requirement, especially in embedded systems where only limited resources are available. Since the memory requirement determined by the dimensionality and the number of support vectors is generally too high for a cache in embedded systems to accomodate, frequent accesses to the main memory occur inevitably whenever the cache is not able to provide requested data to the processor. These frequent accesses to the main memory result in overall performance degradation and increased energy consumption because a memory access typically takes longer and consumes more energy than a cache access or a register access. In this paper, we propose a technique that reduces the number of main memory accesses by optimizing the data access pattern of the SVM-based classifier in such a way that the temporal locality of the accesses increases, fully utilizing data loaded into the processor chip. With experiments, we confirm the enhancement made by the proposed technique in terms of the number of memory accesses, overall execution time, and energy consumption.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.183-190
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• 2021

This study is a study on the implementation and operation of smart air cleaning system to improve indoor air quality. Recently, the problem of indoor air quality is getting serious due to various environmental factors. In this study, to improve the problems of indoor air quality, we implement an air cleaning system using IoT sensor. In particular, we proposed a system that can measure air pollution in real time and change different air flow paths according to pollution level. Through this, we examined efficient air quality improvement, extension of filter life, and system energy reduction. In addition, the main functions of the indoor air quality improvement system were constructed and prototypes were manufactured to confirm the operability. Finally, the utility of fine dust resolution through the implementation of the indoor air quality improvement system was examined.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1882-1890
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• 2014

This paper proposes an augmented Lagrange Hopfield network (ALHN) based method for solving multi-objective short term fixed head hydrothermal scheduling problem. The main objective of the problem is to minimize both total power generation cost and emissions of $NO_x$, $SO_2$, and $CO_2$ over a scheduling period of one day while satisfying power balance, hydraulic, and generator operating limits constraints. The ALHN method is a combination of augmented Lagrange relaxation and continuous Hopfield neural network where the augmented Lagrange function is directly used as the energy function of the network. For implementation of the ALHN based method for solving the problem, ALHN is implemented for obtaining non-dominated solutions and fuzzy set theory is applied for obtaining the best compromise solution. The proposed method has been tested on different systems with different analyses and the obtained results have been compared to those from other methods available in the literature. The result comparisons have indicated that the proposed method is very efficient for solving the problem with good optimal solution and fast computational time. Therefore, the proposed ALHN can be a very favorable method for solving the multi-objective short term fixed head hydrothermal scheduling problems.

• Journal of IKEEE
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• v.24 no.2
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• pp.570-578
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• 2020

In this paper, we propose an efficient method for implementing the adaptive second-order Volterra filter. To reduce computational load, the UCFD-SVF has been proposed. The UCFD-SVF, however, shows deteriorated convergence performance. We propose a new method that initializes the adaptive filter weights periodically on the fact that the energy of the filter weights is slowly increased. Furthermore, we propose another method that the interval for the weight initialization is variable to guarantee the performance and we shows the method gives the better performance under the non-stationary environment through the computer simulation for the adaptive system identification.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.5
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• pp.554-561
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• 2008

This paper deals with an intelligent digital ship which aims at development to support economic and safe services through an integration into the hierarchically layered digital signals such as ship's navigation, maneuvering and control signal and establishing a one-man bridge system in order to provide a support systems between ship and land station. This paper introduces the results of the mid-term project sponsored from Ministry of Commerce, Industry and Energy which consists of three sub-project such as INS(Intelligent Navigation System), AIS(Automatic Identification System), and IMIT (Integrated Maritime Information Technology). The INS system that can allow ships to navigate economically and safely through the integration and analysis of national data within the ship. AIS is a system that reports automatically on the location of the ship in order to prevent the collision between ships and between the ship and the land. IMIT is a integrated system for providing an efficient and economic support system between ships and the land and a ship-land platform and technologies.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.217-224
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• 2011

Existing wire based physical security system solutions show limitations in time and space. In order to solve these deficiencies, a remote physical security system has been implemented using smart phone based on mobile cloud computing technique. The security functions of mobile cloud computing technique include mobile device user authentication, confidentiality of communication, integrity of information, availability of system, and target system access control, authority management and secure hand off etc. Proposed system has been constructed as remote building management system using smart phone, and also has been efficient to reduce energy cost (5~30%), result of system average access and response time 7.082 second. This systems are evaluated to have high efficiency compared to performance.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.766-772
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• 2009

Generally, wind industry has been oriented to large power systems which require large windy areas and often need to overcome environment restrictions. However, small-scale wind turbines are closer to the consumers and have a large market potential, and much more efforts are required to become economically attractive. In this paper, a prototype of a small-scale urban wind generation system for battery charging application is described and a neural network based MPPT(Maximum Power Point Tracking) algorithm which can be effectively applied to urban wind turbine system is proposed. Through Matlab based simulation studies and actual implementation of the proposed algorithm, the feasibility of the proposed scheme is verified.

• Journal of Semiconductor Engineering
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• v.1 no.1
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• pp.57-63
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• 2020

Complementary metal-oxide-semiconductor (CMOS) technology is now facing a power scaling limit to increase integration density. Since 1970s, multi-valued logic (MVL) has been considered as promising alternative to resolve power scaling challenge for increasing information density up to peta-scale level by reducing the system complexity. Over the past several decades, however, a power-scalable and mass-producible MVL technology has been absent so that MVL circuit and system implementation have been delayed. Recently, compact MVL device researches incorporating multiple-switching characteristics in a single device such as 2D heterojunction-based negative-differential resistance (NDR)/transconductance (NDT) devices and quantum-dot/superlattices-based constant intermediate current have been actively performed. Meanwhile, wafer-scale, energy-efficient and variation-tolerant ternary-CMOS (T-CMOS) technology has been demonstrated through commercial foundry. In this review paper, an overview for MVL development history including recent studies will be presented. Then, the status and its future research direction of MVL technology will be discussed focusing on the T-CMOS technology for peta-scale information processing in semiconductor chip.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.5
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• pp.281-296
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• 2015

This paper describes a novel disaster evacuation system using embedded systems such as smart devices for crisis and emergency management. In indoor environments deployed with the Bluetooth Low Energy(BLE) beacons, smart devices detect their indoor positions from beacon messages and interact with Map Server(MS) and Route Server(RS) in the Internet over the LTE and/or Wi-Fi functions. The MS and RS generate an optimal path to the nearest emergency exit based on a novel graph generation method for less route computation, called the Disaster Evacuation Graph(DEG), for each smart device. The DEG also enables efficient processing of some constraints in the computation of route, such as load balancing in situation of different capacities of paths or exits. All data interfaces among three system components, the MS, RS, smart devices, have been defined for modular implementation of our disaster evacuation system. Our experimental system has been deployed and tested in our building thoroughly and gives a good evidence that the modular design of the system and a novel approach to compute emergency route based on the DEG is competitive and viable.

• Journal of Power Electronics
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• v.14 no.3
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• pp.488-498
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• 2014

This paper presents an implementation of selective harmonic elimination (SHE) modulation for a single-phase 13-level transistor-clamped H-bridge (TCHB) based cascaded multilevel inverter. To determine the optimum switching angle of the SHE equations, the Newton-Raphson method is used in solving the transcendental equation describing the fundamental and harmonic components. The proposed SHE scheme used the relationship between the angles and a sinusoidal reference waveform based on voltage-angle equal criteria. The proposed SHE scheme is evaluated through simulation and experimental results. The digital modulator based-SHE scheme using a field-programmable gate array (FPGA) is described and has been implemented on an Altera DE2 board. The proposed SHE is efficient in eliminating the $3^{rd}$, $5^{th}$, $7^{th}$, $9^{th}$ and $11^{th}$ order harmonics, which validates the analytical results. From the results, it can be seen that the adopted 13-level inverter produces a higher quality with a better harmonic profile and sinusoidal shape of the stepped output waveform.