• 한국지진공학회논문집
• /
• 제10권6호
• /
• pp.47-56
• /
• 2006

지진응답 제어를 위하여 사장교 구조물에 장착된 준능동MR 댐퍼의 경제적 효율성 평가기법을 제안하였으며, 다양한 지반운동 특성에 대하여 비용효율성을 극대화하는 MR 댐퍼의 최적용량에 대한 분석을 수행하였다. MR 댐퍼의 비용효율성 평가를 위하여 생애주기비용 개념을 적용하였으며, 생애주기비용을 이루는 비용항목 중 손상비용의 기대값을 평가하기 위하여 지진재해로 인한 사장교의 파괴확률을 추정하였다. 사장교의 파괴로 인한 직 간접 손상비용의 규모를 매개변수로 하여 비용효율성을 평가하였다. 비용효율성 평가지수는 MR 댐퍼의 장착으로 인한 추가 투자비용과 사장교 구조물의 손상비용으로 이루어진 함수로서, 탄성받침이 사용된 기존의 설계에 대한 경제적 효율성을 나타내도록 정의하였다. 사장교의 지진응답 제어를 위하여 장착된 MR 댐퍼는 경제적으로 효율적인 대안인 것으로 나타났다. 지반운동의 특성과 손상비용 규모에 대한 MR 댐퍼의 최적 용량을 분석한 결과, 지진위험도 및 손상비용 규모가 커짐에 따라 가장 높은 비용효율성을 가지는 MR 댐퍼용량이 증가하는 것을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.1020-1022
• /
• 2001

because the output of solar cell is direct, it is necessary to install D/A converter system for A.C load, and in case of driving utility line system, it is possible to drive system relation when the system supplies sinusodal current ant voltage having unit power factor. As the characteristics of the soar cell output the is influenced by dailysunight charge, for more electric power it is essential to control the direction toward the san so that the driving point of solar cell can always operate near maximum output point. PWM modulation device among electric power converters must have stable modulation at anytime when it includes noise-factors such as noise-wave and noises on electric voltage wave, a synchronous signal system. In dealing with synchronous signal for control and control signal by microprocessor, it is necessary to compensate it because there is time difference between sample paint and carrier wave. On this papers, single phase PWM current type invertor controled the solar cell having typical voltage dropping character has optimun short current in short, reduces D.C reactance, composes controller for modulation and keeps lower harmonic and high power factor keeping maximum output of solar cell according daily sunlight charge variation.

• 대한치과교정학회지
• /
• 제26권1호
• /
• pp.95-104
• /
• 1996

본 연구의 목적은 T-Scan system과 근전도를 이용하여 정상교합자와 과개교합자의 최대교합력과 근활성도간의 상관관계를 조사하기 위함이다. 연구대상은 두 집단으로 구성 되었다. 한 집단은 20명의 정상교합자이고 다른 집단은 30명의 과개교합자이다. 과개교합자는 Class I deepbite(9명의 남자와 7명의 여자)와 Class II div. 1 deepbite(8명의 남자와 6명의 여자)로 구성되었다. 이 연구로부터 얻어진 결과는 다음과 같다. 1. 최대교합력은 정상교합군에서 155.93 N, I급 과개교합군에서 165.11 N, II 1류 과개교합군에선 111.55 N이었으며, II급 1류 과개교합군의 최대교합력은 정상교합군에 비해 유의성 있게 낮았다(P<0.01). 2. 정상교합군과 과개교합군 모두에서 치야접촉점이 증가할수록 교합력은 증가하였다(표 3). 3. 최대교합시 II급 1류 과개교합군의 교근 및 전측두근의 근활성도는 전상교합군에 비해 현저히 낮았고(P<0.01),모든 군에서 교근의 활성도가 전측두근보다 높았다(P<0.05). 4. 모든 군에서 교합력과 근활성도, 치아접촉점의 수와 근활성도는 높은 상관관계를 보였다(표 5).

• 전자공학회논문지CI
• /
• 제41권2호
• /
• pp.87-94
• /
• 2004

특징 집합 선택은 학습 알고리즘의 전처리 과정으로 사용되기도 한다. 수집된 자료가 문제와 관련이 없다거나 중복된 정보를 갖고 있는 경우, 이를 학습 모델생성 이전에 제거함으로써 학습의 성능을 향상시킬 수 있다. 또한 탐색 공간을 감소시킬 수 있으며 저장 공간도 줄일 수 있다. 본 논문에서는 특징 집합의 추출과 추출된 특징 집합의 성능 평가를 위하여 엔트로피를 기반으로 한 휴리스틱 함수를 사용하는 새로운 특징 선택 알고리즘을 제안하였다. 탐색 방법으로는 ACS 알고리즘을 이용하였다. 그 결과 학습에 사용될 특징의 차원을 감소시킴으로써 학습 모델의 크기와 불필요한 계산 시간을 감소시킬 수 있었다.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1995년도 춘계 총회 및 학술발표회
• /
• pp.26-27
• /
• 1995

Most of synthetic polymeric membranes used in ultrafiltration, reverse osmosis and microfiltration processes are prepared by phase inversion(or phase separation) technique. In this technique, a homogeneous polymer solution is cast into thin film or hollow fiber shape and then immersed into a nonsolvent coagulant bath. The exchange of solvent and nonsolvent across the interface between casting solution and coagu!ant can make the casting solution phase-separate and form a membrane with a symmetric or asymmetric structure. Because of importance of this technique in membrane field, many investigations have been dedicated to elucidate the mechanism of membrane formation by phase inversion technique.[1-10] These investigation have suggested that the structure formation and permeation properties of phase inversion membrane depend on the variables such as the nature and content of casting solution and coagulant, temperature of casting solution and coagulant, and the diffusional exchange rate of solvent and nonsolvent etc. which can be related to the thermodynamic and kinetic properties of the casting system. The variables such as the nature and content of casting solution can also be the important factor affecting the structure formation and permeation property of the phase inversion membrane.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제19권6호
• /
• pp.59-71
• /
• 2014

We investigated soil contamination depending on the land use by examining the contamination levels and distribution characteristics of 16 polycyclic aromatic hydrocarbons (PAHs) in the national soil. Total PAHs (the sum of 16 PAH concentrations) and carcinogenic PAHs (the sum of seven carcinogenic PAH concentrations) were $8.50{\sim}3,437.16{\mu}g/kg$ and $2.94{\sim}2,136.96{\mu}g/kg$, respectively. The concentration of benzo(a)pyrene, one of the contaminants regulated by the soil quality standard in the nation, was $ND{\sim}924.73{\mu}g/kg$. Its maximum value of $924.73{\mu}g/kg$ was detected in railroad (Region 3) and is approximately 13% of the standard value for Region 3 (i.e., 7 mg/kg). We also investigated the characteristics of contamination sources of PAHs in soil of the upland, forests, roads, and railroads, examining the fraction distribution of PAHs concentration by the number of benzene rings against the total PAHs concentration. The results demonstrate that the mean fraction of 4~6-ring PAHs against total PAHs concentration in soil was in the range of 51.8~80.7% with relative abundance of high-molecular PAHs, showing that the origin of contamination is under the category of combustion sources. When the molecular indices (Flu/(Flu/Pyr), Ant/(Ant+Phe), InP/(InP+BP), and BaA/(BaA+Chr)) were applied, they were also categorized as petroleum-based combustion sources. The individual PAH concentrations in soil by the land use were grouped into Regions 1, 2, and 3, which are statistically treated and are the parts of the national category system of soil quality standard. As a result, the concentration level of 16 PAHs was $0.02{\sim}2.63{\mu}g/kg$ in Region 1, $0.05{\sim}4.26{\mu}g/kg$ in Region 2, and $2.36{\sim}178.27{\mu}g/kg$ in Region 3. The concentration level of 6 carcinogenic PAHs was 14.2~320.4% against that of benzo(a)pyrene in Region 3 and sites of recycling waste sleepers. Considering that there were similarities among PAHs in terms of structures and toxicities, it would be recommended to review other types of carcinogenic PAHs together with benzo(a)pyrene when developing the soil quality standards in the nation.

• Advances in Computational Design
• /
• 제1권4호
• /
• pp.315-327
• /
• 2016

Damage detection and localisation in structures is essential since it can be a means for preventive maintenance of those structures under service conditions. The use of structural modal data for detecting the damage is one of the most efficient methods. This paper presents comparative performance of various state-of-the-art meta-heuristics for use in structural damage detection based on changes in modal data. The metaheuristics include differential evolution (DE), artificial bee colony algorithm (ABC), real-code ant colony optimisation (ACOR), charged system search (ChSS), league championship algorithm (LCA), simulated annealing (SA), particle swarm optimisation (PSO), evolution strategies (ES), teaching-learning-based optimisation (TLBO), adaptive differential evolution (JADE), evolution strategy with covariance matrix adaptation (CMAES), success-history based adaptive differential evolution (SHADE) and SHADE with linear population size reduction (L-SHADE). Three truss structures are used to pose several test problems for structural damage detection. The meta-heuristics are then used to solve the test problems treated as optimisation problems. Comparative performance is carried out where the statistically best algorithms are identified.

• 한국군사과학기술학회지
• /
• 제20권2호
• /
• pp.197-205
• /
• 2017

During the sea trial, we discovered EMI between MOSCOS and ES DF antenna. CW emitted by MOSCOS raised the threshold level of ES DF antenna. As a result, direction finding rate of ES has been decreased. This is a study for the improvement of EMI between the antennas mounted on a surface ship. An analysis is accomplished for MOSCOS, ES DF antenna and Jamming transmitter. This paper presents the method how to solve EMI based on the measurements and calculations about the ES DF antenna receiving level, MOSCOS radiation pattern and Jamming transmitter thermal noise. The test was performed with optimal deployment of MOSCOS on a surface ship. After changing the position of MOSCOS, EMI has been decreased significantly.

• 디지털산업정보학회논문지
• /
• 제13권3호
• /
• pp.19-25
• /
• 2017

Nowadays, networked computer systems play an increasingly important role in our society and its economy. They have become the targets of a wide array of malicious attacks that invariably turn into actual intrusions. This is the reason computer security has become an essential concern for network administrators. Recently, a number of Detection/Prevention System schemes have been proposed based on various technologies. However, the techniques, which have been applied in many systems, are useful only for the existing patterns of intrusion. Therefore, probe detection has become a major security protection technology to detection potential attacks. Probe detection needs to take into account a variety of factors ant the relationship between the various factors to reduce false negative & positive error. It is necessary to develop new technology of probe detection that can find new pattern of probe. In this paper, we propose an hybrid probe detection using Fuzzy Cognitive Map(FCM) and Self Adaptive Module(SAM) in dynamic environment such as Cloud and IoT. Also, in order to verify the proposed method, experiments about measuring detection rate in dynamic environments and possibility of countermeasure against intrusion were performed. From experimental results, decrease of false detection and the possibilities of countermeasures against intrusions were confirmed.

• 정보보호학회논문지
• /
• 제16권3호
• /
• pp.157-164
• /
• 2006

정보사회에서는 사회 구성원 개개인의 욕구를 충족시키는데 정보가 핵심적 역할을 하고 있다. 특히 유비쿼터스 컴퓨팅 환경에서는 개인 활동이 증가함에 따라 개인정보의 노출이 심해지고 개인정보 불법 취득도 점차 많아지고 있다. 이에 본 논문에서는 안전하고 효과적인 개인정보 관리체계와 기술적 구현이 용이하도록 개인정보 프레임워크를 제시하고, 시스템 개발자나 개인정보를 다루는 사업자 측면에서 개인정보 시스템을 설계하고 구현하기에 용이하도록 5단계의 구체적인 방법론을 제시하였다. 특히 제시된 방법론이 실 환경에 효과적으로 활용될 수 있도록 체계적인 개인정보 보호 시스템 개발 방안을 시스템 아키텍처 측면에서 소개함으로써, 본 논문의 활용 방안을 제시하였다. 본 논문에서 제시된 개인정보보호 프레임워크와 방법론은 실제 유비쿼터스 내 점점 중요시 되어가고 있는 개인정보 보호 측면에서의 방향성 제시 및 실제 엔지니어나 개발자 측면에서 이론위주의 설명보다는 실제 활용이 가능한 새로운 접근방안을 제시 할 수 있다고 사료된다.