• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.5
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• pp.266-274
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• 2004

This paper presents a scheme for the interconnection of dispersed generator systems(DGs) based on load .unbalance and load model in composite distribution systems. Groups of each individual load model consist of residential, industrial, commercial, official and agricultural load. The unbalance is involved with many single-phase line segment. . Voltage profile improvement and system loss minimization by installation of DGs depend greatly on how they are placed and operated in the distribution systems. So, DGs can reduce distribution real power losses and replace large-scale generators if they are placed appropriately in the distribution systems. The main idea of solving fuzzy goal programming is to transform the original objective function and constraints into the equivalent multi-objectives functions with fuzzy sets to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithm. The method proposed is applied to IEEE 13 bus and 34 bus test systems to demonstrate its effectiveness.

• Advances in Energy Research
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• v.4 no.4
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• pp.255-274
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• 2016

This paper presents a novel symbiotic organisms search (SOS) algorithm to optimize both real power loss (RPL) and voltage stability limit (VSL) of a transmission network by controlling the variables such as unified power flow controller (UPFC) location, UPFC series injected voltage magnitude and phase angle and transformer taps simultaneously. Mathematically, this issue can be formulated as nonlinear equality and inequality constrained multi objective, multi variable optimization problem with a fitness function integrating both RPL and VSL. The symbiotic organisms search (SOS) algorithm is a nature inspired optimization method based on the biological interactions between the organisms in ecosystem. The advantage of SOS algorithm is that it requires a few control parameters compared to other meta-heuristic algorithms. The proposed SOS algorithm is applied for solving optimum control variables for both single objective and multi-objective optimization problems and tested on New England 39 bus test system. In the single objective optimization problem only RPL minimization is considered. The simulation results of the proposed algorithm have been compared with the results of the algorithms like interior point successive linear programming (IPSLP) and bacteria foraging algorithm (BFA) reported in the literature. The comparison results confirm the efficacy and superiority of the proposed method in optimizing both single and multi objective problems.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.143-152
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• 2005

Optimal methods for designing multiplierless IIR filters with cascaded prefilter-equalizer structures are proposed for narrowband applications. Assuming that an U filter consists of a cyclotomic Polynomial (CP) prefilter and an all-Pole equalizer based on interpolated first order polynomial (IFOP), in the proposed method the prefilter and equalizer are simultaneously designed using mixed integer linear programming (MILP). The resulting filter is a cascaded filter with minimal complexity. In addition, MtP tries to minimize both computational complexity and phase response non-linearity. Design examples demonstrate that the proposed methods produce a more efficient cascaded prefilter-equalizer than existing methods.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.129-137
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• 2004

This paper presents a signature verification method that uses Gabor filter in computing similarity between signatures. In computing similarity to compare two on-line signatures, the temporal relationship between two signatures should be computed in advance. However, conventional point matching method using DP(dynamic programming) matching consumes much computation. In this paper, we propose a fast method for computing the temporal relationship between two on-line signatures by using the phase output of Gabor Inter applied on the on-line signature signals. Two similarity measures are defined in the method: Temporal Similarity and Temporally Arranged Feature Profile Similarity. With the proposed method, Ive could compare signatures 30 times faster than conventional method using DP matching.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.1
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• pp.21-30
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• 2021

Mid-course trajectory of the missiles equipped with seeker should be designed to detect target within FOV of seeker and to maximize the maneuverability at the point of transition to terminal guidance phase. Because the trajectory optimization problems are generally hard to obtain the analytic solutions due to its own nonlinearity with several constraints, the various numerical methods have been presented so far. In this paper, mid-course trajectory optimization problem for boost-glide missiles is calculated by using SOCP (Second-Order Cone Programming) which is one of convex optimization methods. At first, control variable augmentation scheme with a control constraint is suggested to reduce state variables of missile dynamics. And it is reformulated using a normalized time approach to cope with a free final time problem and boost time problem. Then, partial linearization and lossless convexification are used to convexify dynamic equation and control constraint, respectively. Finally, the results of the proposed method are compared with those of state-of-the-art nonlinear optimization method for verification.

• Analytical Science and Technology
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• v.10 no.5
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• pp.350-356
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• 1997

Supercritical Fluid Chromatography(SFC) has been developed as an analytical technique for the compounds that is difficult to analyze by conventional chromatography. Since supercritical fluid $CO_2$ is difficult to elute solutes with high polarity, modified supercritical $CO_2$, was used as a mobile phase. In conventional method, silica column which is saturated with modifier was used. However, with this method, we can not control the quantity of modifier. In this paper, we developed a new method which can control quantity of modifier mixed in supercritical fluid $CO_2$. The quantity of $H_2O$ mixed was measured with amperometric microsensor which was made by perflurosulfonate ionomer(PFSI) film. we have also obtained a good supercritical fluid chromatogram of PAH mixture by use of a modifier composition programming method.

• Applied Biological Chemistry
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• v.26 no.2
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• pp.104-109
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• 1983

Gas chromatographic method for the analysis of phorate(0,0-diethyl S-ethyl-thiomethyl phosphorithioate) and its metabolites in soil and vegetables was studied by using a mixed phase column(10% DC-200+8% Reoplex-400+2% QF-1 on Gas Chrom Q, $1.8{\times}2mm$ i.d, borosilicate glass column). This column can separate completely phorate and its four metabolites except phoratoxon sulfoxide. Retention time of standard mixture ranged 1.8 to 16.1 minutes at column temperature programming from 130 to $200^{\circ}C$ at $5^{\circ}C/min$ and detector sensitivity was also very high(0.05 to 1.05ng). Recoveries from soil and vegetables untreated but fortified with phorate and its three major metabolites at 0.05 and 0.5ppm levels were above 90% for phorate, phorate sulfoxide and phorate sulfone while recovery of phoratoxon metabolite was about 84%.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.3
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• pp.59-66
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• 2022

This study aims to find out how architectural designers applied the design process and what content is applied in the practical process of architectural design in Korea, and to improve it if there is a problem. So the study is carried out by investigating 13 architects(Including one person who wants to keep his work private) with extensive experience in architectural design. The architects were questioned on how and what content the design process was used for their representative works that had been designed. And interviews and field surveys were conducted on other matters to be improved. The survey was conducted from November 2021 to July 2022. According to the conclusion of this study, First, Most architects were applying the design process in the architectural design practice. These are caused by an impact on education, but there was also an aspect of preparation in terms of guidelines such as the Architects Association and storage rights. Second, Although the design process differed in each name and phase, it was generally carried out in the order of the start phase, the planning work phase, the basic design phase, the intermediate design phase, the implementation quarterly, and construction. Third, The step-by-step work of the design process differed slightly depending on the architect, but counseling and contract work were mainly performed at the start-up phase, and field surveys, legal investigations, and case studys were conducted at the planning phase. In the basic design phase, some contents related to architectural programming, basic drawings, images, and models were used as main work contents. In the intermediate design phase, secondary contents such as licensed books and facility facilities were the main tasks. In the implementation design phase, detailed maps and various frost facilities were finally inspected. Since then, construction and supervision have been carried out in the order of progress. Forth, As for the contents to be improved in the future, the architect's ability, the designer's knowledge of the overall architecture, the design supervision system, and the expansion of time for the initial design process were answered.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.5
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• pp.376-381
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• 2019

In this work, we evaluated the structural, electrical and optical properties of $Ge_8Sb_2Te_{11}$ and Cu-doped $Ge_8Sb_2Te_{11}$ thin films prepared by rf-magnetron reactive sputtering. The 200-nm-thick deposited films were annealed in a range of $100{\sim}400^{\circ}C$ using a furnace in an $N_2$ atmosphere. The amorphous-to-crystalline phase changes of the thin films were investigated by X-ray diffraction (XRD), UV-Vis-IR spectrophotometry, a 4-point probe, and a source meter. A one-step phase transformation from amorphous to face-centered-cubic (fcc) and an increase of the crystallization temperature ($T_c$) was observed in the Cu-doped film, which indicates an enhanced thermal stability in the amorphous state. The difference in the optical energy band gap ($E_{op}$) between the amorphous and crystalline phases was relatively large, approximately 0.38~0.41 eV, which is beneficial for reducing the noise in the memory devices. The sheet resistance($R_s$) of the amorphous phase in the Cu-doped film was about 1.5 orders larger than that in undoped film. A large $R_s$ in the amorphous phase will reduce the programming current in the memory device. An increase of threshold voltage ($V_{th}$) was seen in the Cu-doped film, which implied a high thermal efficiency. This suggests that the Cu-doped $Ge_8Sb_2Te_{11}$ thin film is a good candidate for PRAM.

• Journal of Ecology and Environment
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• v.47 no.4
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• pp.187-192
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• 2023

The United States (US) National Science Foundation's (NSF's) National Ecological Observatory Network (NEON) is a continental-scale observation facility, constructed and operated by Battelle, that collects long-term ecological data to better understand and forecast how US ecosystems are changing. All data and samples are collected using standardized methods at 81 field sites across the US and are freely and openly available through the NEON data portal, application programming interface (API), and the NEON Biorepository. NSF led a decade-long design process with the research community, including numerous workshops to inform the key features of NEON, culminating in a formal final design review with an expert panel in 2009. The NEON construction phase began in 2012 and was completed in May 2019, when the observatory began the full operations phase. Full operations are defined as all 81 NEON sites completely built and fully operational, with data being collected using instrumented and observational methods. The intent of the NSF is for NEON operations to continue over a 30-year period. Each challenge encountered, problem solved, and risk realized on NEON offers up lessons learned for constructing and operating distributed ecological data collection infrastructure and data networks. NEON's construction phase included offices, labs, towers, aquatic instrumentation, terrestrial sampling plots, permits, development and testing of the instrumentation and associated cyberinfrastructure, and the development of community-supported collection plans. Although colocation of some sites with existing research sites and use of mostly "off the shelf" instrumentation was part of the design, successful completion of the construction phase required the development of new technologies and software for collecting and processing the hundreds of samples and 5.6 billion data records a day produced across NEON. Continued operation of NEON involves reexamining the decisions made in the past and using the input of the scientific community to evolve, upgrade, and improve data collection and resiliency at the field sites. Successes to date include improvements in flexibility and resilience for aquatic infrastructure designs, improved engagement with the scientific community that uses NEON data, and enhanced methods to deal with obsolescence of the instrumentation and infrastructure across the observatory.