• 디지털융복합연구
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• 제11권5호
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• pp.159-168
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• 2013

본 연구에서는 국내 투자중개매매업을 영위하고 있는 29개 증권사들의 2011년도 실적을 토대로 BSC와 DEA를 결합한 모델을 적용하여 증권회사의 경영효율성을 분석해 보았다. 또한, 경영혁신의 기법으로서 BSC의 논리적 체계에 근거하여 효율성이라는 측면에서 국내증권사들의 경영실태를 평가해 보고자 하였다. 분석결과 고객 효율성 지수가 높은 기업이 종합지수가 높은 경향이 있는 것으로 나타나 고객관점 지수가 국내 증권사들의 종합 경영 효율성 산정에 중요한 요인으로 작용하고 있는 것으로 확인되었다. 또한 효율성 분석결과를 바탕으로 증권사들의 전통적 재무비율인 ROI와 ROA 등 수익성 비율과 효율성지수의 상관관계 분석을 실시한 결과 유의미한 양의 상관관계를 보여 BSC관점의 경영 효율성이 높은 기업들이 수익성 측면에서도 좋은 실적을 기록하고 있음을 확인하였다. 본 연구에서 제시한 BSC-DEA 결합모델은 증권업 분야 뿐 아니라 다른 산업 분야에서도 경영 효율성을 판단하는 좋은 경영지표로 활용되어질 것으로 기대되며, 기업의 유 무형자산에 대한 가치 평가를 통합할 수 있는 균형모델로 사용될 것으로 기대된다.

• Molecules and Cells
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• 제23권1호
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• pp.72-79
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• 2007

Demand for low-input sustainable crop cultivation is increasing to meet the need for environment-friendly agriculture. Consequently, developing genotypes with high nutrient use efficiency is one of the major objectives of crop breeding programs. This study was conducted to identify QTLs for traits associated with physiological nitrogen use efficiency (PNUE). A recombinant inbred population (DT-RILs) between Dasanbyeo (a tongil type rice, derived from an indica ${\times}$ japonica cross and similar to indica in its genetic make-up) and TR22183 (a Chinese japonica variety) consisting of 166 $F_8$ lines was developed and used for mapping. A frame map of 1,409 cM containing 113 SSR and 103 STS markers with an average interval of 6.5 cM between adjacent marker loci was constructed using the DT-RILs. The RILs were cultivated in ordinary-N ($N-P_2O_5-K_2O=100-80-80kg/ha$) and low-N ($N-P_2O_5-K_2O=50-80-80kg/ha$) (100 kg/ha) conditions. PNUE was positively correlated with the harvest index and grain yield in both conditions. Twenty single QTLs (S-QTLs) and 58 pairs of epistatic loci (E-QTLs) were identified for the nitrogen concentration of grain, nitrogen concentration of straw, nitrogen content of shoot, harvest index, grain yield, straw yield and PNUE in both conditions. The phenotypic variance explained by these S-QTLs and E-QTLs ranged from 11.1 to 44.3% and from 16.0% to 63.6%, respectively. The total phenotypic variance explained by all the QTLs for each trait ranged from 35.8% to 71.3%, showing that the expression of PNUE and related characters depends signify- cantly upon genetic factors. Both S-QTLs and E-QTLs may be useful for marker-assisted selection (MAS) to develop higher PNUE genotypes.

• 한국환경농학회지
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• 제25권3호
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• pp.195-201
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• 2006

The operational characteristics of anaerobic bioreactors in treating swine wastewater were evaluated upto hydraulic retention time (HRT) of 1 day and organic loading rate (OLR) of $5.1kg-COD/m^3{\cdot}d$ for 200 days. The bioreactors were effective in treating swine wastewaters with COD removal efficiency of $78.9{\sim}81.5%$ and biogas generation of $0.39{\sim}0.59m^3/kg-COD_r$ at OLR of $1.1{\sim}2.2kg-COD/m^3{\cdot}d$. The two-stage ASBF anaerobic bioreactors was effective in treating different characteristics of swine wastewaters since they showed high and stable COD removal efficiency at high OLR due to effective retention of biomass by media and staging. The effects of ammonia on anaerobic digestion were investigated by operating two-stage ASBF reactors using swine wastewaters as influent without and with ammonia removal at HRT of $1{\sim}2$ days and OLR of $2.2{\sim}9.6kg-COD/m^3{\cdot}d$ for 250 days. The COD removal efficiency and biogas generation of two-stage ASBF reactors was decreased by increasing influent ammonia concentrations to 1,580 mg (T-N)/L with increasing OLR to $6.3kg-COD/m^3{\cdot}d$, while those were increased by maintaining influent ammonia concentrations below 340 mg (T-N)/L by MAP precipitation with increasing OLR to $9.6kg-COD/m^3{\cdot}d$. Initial inhibition of ammonia on anaerobic processes was observed at a concentration of 760 mg (T-N)/L and the COD removal efficiency and biogas generation dropped to 1/2 at ammonia concentration ranges of $1,540{\sim}1,870mg$ (T-N)/L. It is essential to remove ammonia in swine wastewaters to an initial inhibition level before anaerobic processes for the effective removal of COD.

• 한국컴퓨터정보학회논문지
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• 제10권1호
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• pp.201-208
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• 2005

오늘날 컨테이너터미널의 운영방식의 변화를 통해 컨테이너터미널의 효율을 증대시키기 위한 대처방안에 대한 연구가 활발히 이루어지고 있다. 컨테이너터미널의 효율을 증대시키기 위해서는 적하계획 수립이 상당히 중요한 역할을 한다. 적하계획은 크게 적재의 위치를 결정하는 문제와 적재의 순서를 결정하는 문제로 나눌 수 있는데, 본 논문에서는 보다 효율적인 적재순서 결정 방안을 제시한다. 컨테이너 적재순서 결정 문제는 장치위치 및 운영 장비 등 여러 가지 경우의 수를 고려해야 하는 조합 최적화 문제이다. 컨테이너 적재순서를 결정하는 기존의 클러스터 구성방식은 재처리 문제로 작업의 효율성을 높이는데 한계가 있다. 따라서 선적지시서와 야드맵을 기초로 동일한 속성을 가진 컨테이너들을 계층적 클러스터링 방법을 적용하여 스택단위의 클러스터로 구성하고, 작업순서의 제약을 정의하는 보다 효율적인 컨테이너 적재순서결정 방법을 제안한다. 그 과정에서 작업순서 제약을 정의함으로서 클러스터간의 가능한 작업경로를 파악할 수 있고, 작업경로에 대한 제약적 탐색이 가능하여 기존의 방식에 비해 탐색효율이 증가됨을 알 수 있다.

• Investigative Magnetic Resonance Imaging
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• 제15권2호
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• pp.110-122
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• 2011

목적 : 본 연구의 목적은 확산텐서영상에 기반하여 한국 아동 집단의 해부학적 뇌연결성 지도를 확립하고 뇌신경망의 효율성을 평가하는 기법을 개발하는 것이다. 대상 및 방법 : 건강한 아동 12명에서 얻은 확산텐서영상과 뇌구획영상을 바탕으로 구조 연결 행렬을 구하여 집단의 구조 연결성을 평가하였다. 일표본 t-검정을 시행하여 평균적인 구조 연결성을 파악하였고 이 때 얻은 각 피험자의 백질 다발을 표준공간으로 정규화하여 집단의 해부학적 뇌연결망 지도를 확립했다. 뇌신경망의 군집정도(clustering coefficient), 평균이동거리(characteristic path length), 전체/부분 연결망 효율성(global/local efficiency) 등 연결망 속성을 계산한 후 시각화 하였다. 결과 : 연결망 측면에서 한국 아동 집단의 뇌연결성이 작은세상속성을 가짐을 밝혔다. 또한 해부학적 뇌연결망 지도를 얻었는데 대뇌 반구 내의 연결성이 높게 나타남과 뇌간과 운동/감각 영역간에 많은 신경 연결이 집중되어 있음을 확인하였다. 결론 : 한국 아동 집단의 해부학적 뇌연결망 지도를 작성하는 방법론을 제시하여 뇌를 연결성 측면에서 이해하고 발달 장애와 성인 뇌신경망의 효율성을 평가할 수 있는 기본 도구를 확립하게되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.600-619
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• 2015

We propose a cost-efficient hybrid algorithm for online location updates that efficiently combines feature point detection with the online trajectory-based sampling algorithm. Our algorithm is designed to minimize the average trajectory error with the minimal number of sample points. The algorithm is composed of 3 steps. First, we choose corner points from the map as sample points because they will most likely cause fewer trajectory errors. By employing the online trajectory sampling algorithm as the second step, our algorithm detects several missing and important sample points to prevent unwanted trajectory errors. The final step improves cost efficiency by eliminating redundant sample points on straight paths. We evaluate the proposed algorithm with real GPS trajectory data for various bus routes and compare our algorithm with the existing one. Simulation results show that our algorithm decreases the average trajectory error 28% compared to the existing one. In terms of cost efficiency, simulation results show that our algorithm is 29% more cost efficient than the existing one with real GPS trajectory data.

• 소성∙가공
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• 제10권4호
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• pp.347-354
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• 2001

Compression tests were carried out to investigate the hot-deformation behavior of Ti-6Al-4V alloy in the temperature range of $915^{\circ}C$ to $1015^{\circ}C$ and the strain rate range of $10^{-3}s^{-i}$ to $10s^{-1}$. Under the given test conditions, the hot-deformation of Ti-6Al-4V alloy was mainly led by dynamic recovery rather than by dynamic recrystallization. The activation energy for the plastic deformation in $\alpha+\beta$ field was about 894 kJ/mol and $\beta$ field was 332kJ/mo1. Processing map for hot working are developed on the basis of the variations of efficiency of power dissipation($\eta$=2m/m＋1) and flow instability criterion using the dynamic material model. The optimum process condition in the ($\alpha＋\beta$) field was obtained at the temperature ranges of $930^{\circ}C$ to $955^{\circ}C$$^{\circ}C$ and a strain rate of $10^{-3}s{-1}$.

• 자원환경지질
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• 제31권6호
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• pp.557-567
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• 1998

In order to utilize the data obtained during the deep-sea resources exploration program, the analysis of data structure and database were conducted to develop an appropriate data operating system called Deep-sea Database System. The Relation Data Base Management System, RDBMS, was chosen as a data managing system and the MS Access$^{TM}$ as a DB engine, and the MapInfo$^{TM}$ software as GIS tools. Problems in networking and security were detected and solved during the operation test. Accordingly, development of standardized operative procedure was proposed in obtaining raw data. This proposal will also be reflected in the subsequent phase of the deep-sea program. The Deep-sea Database System could be applied to the selection of potential mining sites and the estimation of economical efficiency over th KODOS (Korea Deep Ocean Study) region. It is also expected that this system might improve the efficiency of detail survey and help in the relinquishment process as a fulfillment of the obligation as a pioneer investor.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.541-544
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• 2005

This study presents the integrated modeling approach to simulate the proton exchange membrane (PEM) fuel cell system for vehicle application. The fuel cell system consisting of stack and balance of plant (BOP) was simulated with MATLAB/Simulink environment to estimate the maximum system power and investigate the effect of BOP component sizing on system performance and efficiency. The PEM fuel cell stack model was established by using a semi-empirical modeling. To maximize the net efficiency of fuel cel1 system, multi-variable optimization code was adopted. Using this method the optimized operating values were obtained according to various system net power levels. The fuel cell model established was co-linked to AVL CRUISE, a vehicle simulation package. Through the vehicle simulation software, the fuel economy of fuel cell powered electric vehicle for two types of driving cycles was presented and compared. It is expected that this study tan be effectively employed in the basic BOP component sizing and in establishing system operation map with respect to net power level of fuel cell system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1785-1801
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• 2017

In recent years, image encryption algorithms have been developed rapidly in order to ensure the security of image transmission. With the assistance of our previous work, this paper proposes a novel chaotic image encryption algorithm based on self-adaptive model and feedback mechanism to enhance the security and improve the efficiency. Different from other existing methods where the permutation is performed by the self-adaptive model, the initial values of iteration are generated in a novel way to make the distribution of initial values more uniform. Unlike the other schemes which is on the strength of the feedback mechanism in the stage of diffusion, the piecewise linear chaotic map is first introduced to produce the intermediate values for the sake of resisting the differential attack. The security and efficiency analysis has been performed. We measure our scheme through comprehensive simulations, considering key sensitivity, key space, encryption speed, and resistance to common attacks, especially differential attack.