• 전기전자학회논문지
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• 제23권3호
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• pp.858-864
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• 2019

본 논문에서는 센서 유틸리티 네트워크에서 센서 노드들 사이의 주파수 차이로 인한 데이터 손실을 제거하기 위한 클록 시스템이 제안된다. 각 센서 노드를 위한 제안된 클록 시스템은 버스트 클록-데이터 복원 회로, 32-위상 클록을 출력하는 디지털 위상 고정 루프, 그리고 프로그래밍 가능한 개방형 루프 분수 분할기를 사용하는 디지털 주파수 합성기로 구성된다. 첫번째 센서 노드에는 버스트 클록-데이터 복원 회로 대신 능동 인덕터를 사용하는 CMOS 발진기가 사용된다. 제안된 클록 시스템은 1.2 V 공급 전압을 이용하는 65nm CMOS 공정에서 설계된다. 센서 노드들 사이의 주파수 오류가 1%일 때, 제안하는 버스트 클록-데이터 복원 회로는 기준 클록으로 5Mbps 데이터 속도에 대해 64배 체배된 주파수를 가짐으로 4.95 ns의 시간지터를 가진다. 설계된 디지털 주파수 합성기의 주파수 변경은 100 kHz에서 320 MHz의 주파수 범위에서 출력 클록의 한 주기 내에 수행된다.

• 국토계획
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• 제54권3호
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• pp.15-26
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• 2019

The development of science and transportation technology leads to the increase of inter - city networks that play an important role in urban growth. Overall, numerous studies based on network theory pay attention to positive effects of urban network on urban growth. However, some studies have pointed out the negative effects of inter-city interactions such as straw effects. This implies that the network between cities may not be positively correlated with urban growth, and that the direction of the influence may vary from a certain threshold, such as the marginal utility curve. In this context, the purpose of this study is to measure the impacts of network with central city on urban growth in the capital region and examine the relationship between urban network and growth. Two multiple regression models are employed with changes in population and employment as dependent variables. The urban network index and other control variables are used as independent variables. Especially, the urban network indexes are used in quadratic forms to examine non linear relations with urban growth such U-shape or an inverted U-shape. The results show that the relationships between networks with the central city and urban growth are not a simple linear, and the influence can be changed from the critical point.

• 대한전자공학회논문지TC
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• 제39권6호
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• pp.19-19
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• 2002

본 고에서는 최선형 인터넷 서비스에 대해서 대역공유량의 변화가 가지는 특성을 이론적으로 모델링하는 방법을 제안한다. 그리고 유틸리티에 기반한 요금정책을 제안하고 수치실험을 통해 제안방법의 의의와 효과에 대해 검토한다.

• 대한전자공학회논문지TC
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• 제39권6호
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• pp.277-284
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• 2002

본 고에서는 최선형 인터넷 서비스에 대해서 대역공유량의 변화가 가지는 특성을 이론적으로 모델링하는 방법을 제안한다. 그리고 유틸리티에 기반한 요금정책을 제안하고 수치실험을 통해 제안방법의 의의와 효과에 대해 검토한다.

• Journal of the Optical Society of Korea
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• 제12권3호
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• pp.166-169
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• 2008

The submersion monitoring system based on a reflective side-polished optical fiber submersion sensor with an optical fiber mirror was shown to be an effective alarm system with remote monitoringwhen the drainage capacity of a common utility duct is exceeded due to heavy rainfall. The proposed sensor was connected to an existing installed optical fiber network at a height of 250mm in a common utility duct, and then tested under sample materials(distilled water, river water, sea water, foul water, muddy water, petroleum, edible oil) at a distance of 1km from the sensor for remote sensing. In experiments, the proposed real-time sensor system reduced maintenance cost and improved monitoring efficiency by using a reflection-type side-polished optical fiber submersion sensor efficient for remote monitoring of a common utility duct.

• 대한산업공학회지
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• 제28권1호
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• pp.112-127
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• 2002

A useful pattern is a pattern that contributes much to learning. For a classification problem those patterns near the class boundary surfaces carry more information to the classifier. For a regression problem the ones near the estimated surface carry more information. In both cases, the usefulness is defined only for those patterns either without error or with negligible error. Using only the useful patterns gives several benefits. First, computational complexity in memory and time for learning is decreased. Second, overfitting is avoided even when the learner is over-sized. Third, learning results in more stable learners. In this paper, we propose a pattern 'utility index' that measures the utility of an individual pattern. The utility index is based on the bias and variance of a pattern trained by a network ensemble. In classification, the pattern with a low bias and a high variance gets a high score. In regression, on the other hand, the one with a low bias and a low variance gets a high score. Based on the distribution of the utility index, the original training set is divided into a high-score group and a low-score group. Only the high-score group is then used for training. The proposed method is tested on synthetic and real-world benchmark datasets. The proposed approach gives a better or at least similar performance.

• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.49-58
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• 2023

Renewable energy is not a new terminology. One of the fastest growing renewable energies is solar energy. The implementation of solar energy provides several advantages including the reduction of some of the environmental risks of fossil fuel consumption. This research elaborated the importance of the adaption of solar energy by developing a spatial decision support system (SDSS), while the Residential Solar Energy Adoption (RSEA) is an instantiation artifact in the form of an SDSS. As a GIS web-based application, RSEA allows stakeholders (e.g., utility companies, policymakers, service providers homeowners, and researchers) to navigate through locations on a map interactively. The maps highlight locations with high and low solar energy adoption potential that enables decision-makers (e.g., policymakers, solar firms, utility companies, and nonprofit organizations) to make decisions. A combined qualitative and quantitative methodological approach was used to evaluate the application's usability and user experience, and results affirmed the ability of the factors of utility, usefulness, and a positive user experience of the residential solar energy adoption of spatial decision support system (RSEA-SDSS). RSEA-SDSS in improving the decision-making process for potential various stakeholders, in utility, solar installations, policy making, and non-profit renewable energy domains.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3071-3095
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• 2013

Configuring optimization of wireless sensor networks, which can improve the network performance such as utilization efficiency and network lifetime with minimal energy, has received considerable attention in recent years. In this paper, a cross layer optimal approach is proposed for multi-source linear network and grid network under Rayleigh block-fading channels, which not only achieves an optimal utility but also guarantees the end-to-end reliability. Specifically, in this paper, we first strictly present the optimization method for optimal nodal number $N^*$, nodal placement $d^*$ and nodal transmission structure $p^*$ under constraints of minimum total energy consumption and minimum unit data transmitting energy consumption. Then, based on the facts that nodal energy consumption is higher for those nodes near the sink and those nodes far from the sink may have remaining energy, a cross layer optimal design is proposed to achieve balanced network energy consumption. The design adopts lower reliability requirement and shorter transmission distance for nodes near the sink, and adopts higher reliability requirement and farther transmission distance for nodes far from the sink, the solvability conditions is given as well. In the end, both the theoretical analysis and experimental results for performance evaluation show that the optimal design indeed can improve the network lifetime by 20-50%, network utility by 20% and guarantee desire level of reliability.

• 한국철도학회논문집
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• 제11권1호
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• pp.45-53
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• 2008

본 연구는 중장기적 고속철도망 계획을 위한 투자우선순위를 전통적인 평가기법에서 벗어나 지속가능 한 교통의 관점에서 이를 분석할 수 있는 방법론을 제안하고, 다원-개준 의사결정기법 중의 하나인 다원-속성 효용이론(MAUT)을 이용하여 이를 분석하였다. 지속가능 한 교통지표는 경제지표, 사회지표 및 환경지표로 구분하였으며, 지속가능 한 고속철도망 지수 분석 결과 경부와 호남 고속철도 이후에 건설되어야 할 우리나라의 고속철도망 노선축의 투자우선순위는 동서축, 남해축, 서해축 등의 순서로 분석되었다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권5호
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• pp.280-286
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• 2006

The paper proposes a new protection algorithm for reliable operation of grid-interfaced PV system, which can flexibly interact with conventional protective schemes of power utility grid not only to prevent damages to utility or public persons and utility apparatus caused by malfunction or failure in distribution network protection system, but also to protect a PV system itself from faults or abnormal conditions of the network. The proposed algorithm is based on reclosing characteristics of the distribution system. As a network fault occurs, the new scheme determines whether it is momentary or permanent and responds in a pre-programmed way to the fault. For permanent outage, the proposed algorithm shuts down inverter's operations but monitoring system voltage and frequency at the point of common coupling with grid. When it comes to the momentary outage, Inverter starts stand-by operation mode so that it can be automatically connected to the grid without start-up procedures as soon as the system voltage and frequency returns into the normal operation range. In order to investigate' and evaluate the PV system operation, simulation study based on PSCAD/EMTDC has been carried out to verify the performance of the proposed protection scheme.