• Advances in Energy Research
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• v.6 no.1
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• pp.55-73
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• 2019

The cost incurred by voltage sag effect in power networks has always been of important concern for discussions. Due to the environmental constraints, fossil fuel shortage crisis and low efficiency of conventional power plants, decentralized generation and renewable based DG have become trends in recent decades; because DGs can reduce the voltage sag effect in distribution networks noticeably; therefore, optimum allocation of DGs in order to maximize their effectiveness is highly important in order to maximize their effectiveness. In this paper, a new method is proposed for calculating the cost incurred by voltage sag effect in power networks. Thus, a new objective function is provided that comprehends technical standards as minimization of the cost incurred by voltage sag effect, active power losses and economic criterion as the installation and maintenance costs of DGs. Considering operational constraints of the system, the optimum allocation of DGs is a constrained optimization problem in which Lightning Attachment procedure optimization (LAPO) is used to resolve it and is the optimum number, size and location of DGs are determined in IEEE 33 bus test system and IEEE 34 bus test system. The results show that optimum allocation of DGs not only reduces the cost incurred by voltage sag effect, but also improves the other characteristics of the system.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3925-3932
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• 2024

During outages at nuclear power plants, much more care for radiation workers against internal exposure should be ensured given that more hot particles exist relative to the amount during normal operation. If fuel-type hot particles (FTHP) are inhaled, they can cause more severe health risks compared to activation-type hot particles (ATHP), which contain ⁶⁰Co, due to the alpha-emitting nuclides within FTHPs. The activities of difficult-to-measure nuclides within FTHPs inhaled by workers are inferred by the age-dating technique using a¹⁴¹Ce/¹⁴⁴Ce ratio as measured by whole-body counters. However, this method may be limited to outages that last for only a few months due to the short half-life (32.5 days) of ¹⁴¹Ce. We studied the feasibility of utilizing ²⁴¹Am, a nuclide with a long half-life of 432.6 years, as an alternative to ¹⁴¹Ce. Additionally, we improved the performance of a stand-type whole-body counter for low-energy gamma spectroscopy to meet the criterion (RMSE ≤0.25) specified in ANSI/HPS N13.30-2011 by employing an artificial neural network (ANN). This study can contribute to more rapid and accurate internal dose assessments for workers who have inhaled FTHPs during long-term outages at nuclear power plants.

• International Journal of Advanced Culture Technology
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• v.2 no.2
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• pp.1-6
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• 2014

In this paper, we propose an intelligent streetlight system that has a complex sensor module of temperature, humidity, luminance and motion detection and controlled by the fuzzy logic based central monitoring system in order to get flexible and precise manipulation of the streetlight system in USN environment. The proposed streetlight system provides low power consumption and high efficiency by using sensed data from the complex sensor module, which were collected, processed, and analyzed by the fuzzy logic based central monitoring system. The performance of the proposed streetlight system is to be evaluated by a simulation study in terms of power savings and safety at the fields constructed as a test-bed under several suggested scenarios. Finally, we know that the proposed intelligent streetlight system can maximize the energy savings efficiently with the fuzzy logic based central monitoring system and selective remote dimming control by connecting it to the wireless ubiquitous sensor network (USN) using a Zigbee module.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.159-162
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• 2002

A software, called touch-one, is developed about the determination of short-circuit values and protective co-ordination in power system. The used solution algorithm reviewed intensively, and the protective co-ordination determination technique presented by using the circuit-breaker's current-limitation characteristic. The protective coordination concerns the behaviour of two devices placed in series in an electrical network, with a short-circuit downstream circuit-breaker. It has two basic principles: First, discrimination which is an increasing requirement of low voltage electrical distribution systems. Second, which is less well known: cascading, which consists of installing a device, whose breaking capacity is less than the three-phase short-circuit current at its terminals and helped by main circuit-breaker. With this software, we can construct a electric-power system which is reliable and economic according to user's purpose.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.205-207
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• 2000

본 논문에서는 전력선을 통신 매체로 한전력선 통신시 전력선상에 항시 존재하는 전원 주파수의 고조파와 부하로 인한 고조파 부하 투입시 발생하는 임펄스형 잡음이 통신신호에 미치는 영향과 그 특징을 조사하였다. 통신 신호에 미치는 영향을 측정하기 위하여 모의 실험을 위한 별도의 전력선을 설치하였다. 또한 실제 전력선 통신을 재현하기 위하여 HTH사와 Intelogis사의 전력선 모뎀을 사용하였으며, 고조파 성분과 임펄스형 잡음의 실현을 위하여 인버터, 고조파 발생장치, 스위칭 부하를 설계하여 사용하였다.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1735-1742
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• 2016

This paper proposes an interleaved five-level boost converter based on a switched-capacitor network. The operating principle of the converter under the CCM mode is analyzed. A high voltage gain, low component stress, small input current ripple, and self-balancing function for the capacitor voltages in the switched-capacitor networks are achieved. In addition, a three-loop control strategy including an outer voltage loop, an inner current loop and a voltage-balance loop has been researched to achieve good performances and voltage-balance effect. An experimental study has been done to verify the correctness and feasibility of the proposed converter and control strategy.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2006.05a
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• pp.143-147
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• 2006

Wireless sensor networks(WSN) technology has various applications such as surveillance and information gathering in the uncontrollable area of human. One of major issues in WSN is the research for reducing the energy consumption and reliability of data. A system with forward error correction(FEC) can provide an objective reliability while using less transmission power than a system without FEC. In this paper, we propose to use LDPC codes of various code rate(0.53, 0.81, 0.91) for FEC for WSN. Also, we considered node-to-node interference in addition to AWGN channel. The proposed system has not only high reliable data transmission at low SNR, but also reduced transmission power usage.

• Journal of Power Electronics
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• v.14 no.5
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• pp.834-841
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• 2014

This paper proposes new active switched-capacitor and switched-inductor Z-source inverter (ASC/SL-ZSI) topologies, which can provide a higher boost ability with a small shoot-through time. The proposed ASC/SL-ZSIs inherit all of the advantages of the classical ZSI, and have a stronger voltage boost inversion ability when compared with the classical ZSI. Thus, the output ac voltage quality is significantly improved. In addition, more cells can be cascaded in the impedance network in order to obtain a very high boost ability. The proposed topologies can be applied to photovoltaic or fuel-cell generation systems with low-voltage renewal sources due to their wide range of obtainable voltages. Both simulations and the experimental results are carried out in order to verify performance of the proposed topologies.

• Journal of the Korea Society of Computer and Information
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• v.8 no.3
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• pp.138-143
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• 2003

With information communications and network environments merged wire/wireless networks are generalized. In this viewpoint, WAP is used by communication protocol for the data communication in the field of wireless environment. WTLS developed for the secure communications optimize TLS adapted wireless environment in the TCP/IP internet protocol. But WTLS denote WAP security problem, end-to-end problem, and power consumption, etc. Therefore in this paper we proposed WTLS cryptographic algorithm eliminated WTLS disadvantages. Proposed algorithm solved power consumption, calculated complexity, and security problems because it is not unique but hybrid form.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.754-756
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• 2003

DNA칩 기술로 얻어지는 대규모 섭동데이터(perturbation data)는 생물학적시스템(biological system)의 유전자네트워크(genetic network)를 재구성(reverse-engineering)하는데 있어 유용하다. 그러나 기존의 연구는 유전자 조절 관계의 규명이나 혹은 데이터를 설명하는 최적의 모델을 찾는 방향에만 관심을 두고 있고. 실험적인 한계로 인한 DNA칩 데이터의 오류가 재구성된 네트워크의 구조에 미치는 영향에 대해서는 중요하게 다루고 있지 않다. 본 논문에서는 유전자 네트워크의 멱함수(power-low) 분포 구조를 이용하여, 섭동 데이터의 오류가 재구성된 네트워크의 토폴로지(topology)에 미치는 영향을 분석하였다. 가상의 네트워크에 대한 데이터를 사용하여 실험한 결과, 데이터의 오류 정도에 따른 네트워크 토폴로지의 변형 양상을 관측할 수 있었다.