차세대 태양전지 하이브리드 기술의 전망

이재관,이재준,Lee, Jae-Kwan,Lee, Jae-Joon 한국전기화학회 2010 한국전기화학회지 Vol.13 No.1

본 논문에서는 주요 차세대 태양전지로 분류되는 염료감응 태양전지와 유기(고분자)태양전지에 대한 연구 동향을 살펴보고 이들의 하이브리드 기술전망에 관해 살펴보았다. 특히 두 분야는 기존 무기물 소재의 태양전지와의 경쟁력을 제고하기 위한 측면에서도 상호 전략적인 기술융합을 통한 하이브리드 기술의 개발이 필요한 시점이다. 기술적으로나 시기적으로 아직 초기단계임에도 기술융합에 대한 새로운 응용 가능성에 많은 관심을 끌고 있을 뿐 아니라 성공적인 융합기술 개발의 파급효과도 매우 클 것으로 예상된다. We are presenting an overview of a R&D trend on dye-sensitized solar cells and organic polymer solar cells, which are classified into a next-generation solar cell, and the perspective on their hybridization technology. When considering the competition with inorganic material-base solar cells, especially, these next-generation solar cells need a new hybridization technology, even though it is still at the initial stage. The fusion and hybridization of them will be not only attractive in a new application, but also promising to expect significant progresses in the near future for successful R&D.

여산믹스문제를 위한 발견적접근

이재관,Lee Jae-Kwan 한국국방경영분석학회 1980 한국국방경영분석학회지 Vol.6 No.1

An effectively designed budget system in the poor resources environment necessarily has three design criteria : (i) to be both planning-oriented and control-oriented, (ii) to be both rationalistic and realistic, (iii) to be sensitive to the variations of resources environment. PPB system is an extreme (planning-oriented and rationalistic) and conventional OEB/OUB system is the other extreme (control-oriented and incrementalistic). Generally, the merits of rationalism are limited because of the infeasibility of applications. Hence, mixtures of the two extremes such as MBO, ZBB, and RZBB have been examined and applied during the last decade. The classical mathematical models of capital budgeting are the starting points of the development of the Budget-Mix Model introduced in this paper. They are modified by the followings: (i) technological-resource constraints, (ii) bounded-variable constraint, (iii) the exchange rules. Special emphasis is laid on the above (iii), because we need more efficient interresource exchanges in the budget-mix process. The Budget-Mix Model is not based on optimization, but a heuristic approach which assures a satisficing solution. And the application fields of this model range between the incremental Nonzero-Base Budgeting and the rational Zero-Base Budgeting. In this thesis, the author suggests 'the budget- mix concept' and a budget-mix model. Budget-mix is a decision process of making program-mix and resource-mix together. For keeping this concept in the existing organization realistic, we need the development of quantitative models describing budget-mix situations.

C(sI-A)^-1B가 최소위상이 될 LMI 조건을 이용한 해석과 설계

이재관,최한호,Lee Jae-Kwan,Choi Han Ho 제어로봇시스템학회 2005 제어·로봇·시스템학회 논문지 Vol.11 No.11

We derive a linear matrix inequality(LMI) condition guaranteeing that any invariant zeros of a triple (A, B, C) lie in the open left half plane of the complex plane, i.e. $C(sI-A)^{-1}B$ is minimum phase. The LMI condition is equivalent to a certain constrained Lyapunov matrix equation which can be found in many results relating to stability analysis or control design. We show that the LMI condition can be used to simplify various control engineering problems such as a dynamic output feedback control problem, a variable structure static output feedback control problem, and a nonlinear system observer design problem. Finally, we give some numerical examples.

초신성 잔해와 항성풍 공동간의 상호 작용

이재관,구본철,Lee, Jae-Kwan,Koo, Bon-Chul 한국천문학회 1997 天文學論叢 Vol.12 No.1

We have developed a spherical FCT code in order to simulate the interaction of supernova remnants with stellar wind bubbles. We assume that the density profile of the supernova ejecta follows the Chevalier mode1(1982) where the outer portion has a power-law density distribution($\rho{\propto}\gamma^{-n}$) and the SN ejecta has a kinetic energy of $10^{51}$ ergs. The structure of wind bubble has been calculated with the stellar mass loss rate $\dot{M}=5\times10^{-6}M_{\odot}/yr$ and the wind velocity $\upsilon=2\times10^3$ km/s We have simulated seven models with different initial conditions In the first two models we computed the evolution of SNRs with n=7 and n=14 in the uniform medium The numerical results agree with the Chevalier's similarity solution at early times. When all of the power-law portion of the ejecta is swept up by the reverse shock, the evolution slowly converges to the Sedov-Taylor stage. There is not much difference between the two cases with different n's The other five models simulate SNRs produced inside wind bubbles. In model III, we consider the SN ejecta of 1.4 $M_{\odot}$ and the radius of bubble ~2.76 pc so that ratio of the mass $\alpha(=M_{W.S}/M_{ej}$ is 2. We follow the complex hydrodynamic flows produced by the interaction of SN shocks with stellar shocks and with the contact discontinuities, In the model III, the time scale for the SN shock to cross the wind shell $\tau_{cross}$ is similar to the time scale for the reverse shock to sweep the power-law density profile $\tau_{bend}$. Hence the SN shock crosses the wind shell. At late times SN shock produces another shell in the ambient medium so that we have a SNR with double shell structure. From the numerical results of the remaining models, we have found that when $\tau_{cross}/\tau_{bend}\leq2$, or equivalently when $\alpha\leq50$, the SNRs produced inside wind bubbles have double shell structure. Otherwise, either the SN shock does not cross the wind shell or even if it crosses at one time, the reverse shock reflected at the center accelerates the wind shell to merge into the SN shock Our results confirm the conclusion of Tenorio-Tagle et a1(1990).

상악동을 천공한 임플란트의 생존율에 대한 후향적 연구

이재관,엄흥식,장범석,Lee, Jae-Kwan,Um, Heung-Sik,Chang, Beom-Seok 대한치주과학회 2006 Journal of Periodontal & Implant Science Vol.36 No.4

Perforation of maxillary sinus is a common complication of implant placement in posterior maxilla. The purpose of this study was to evaluate the prognosis of sinus perforated implants placed in partially edentulous maxillae. Eighteen sinus perforated implants in 15 patients were examined for cumulative survival rate, radiographic preoperative bone level, and radiographic marginal bone level change. Twenty-two non-perforated implants in the same patients served as control. The results were as follows; 1. There was no statistically significant difference in cumulative survival rate between sinus perforated implants and non-perforated implants (P>0.05). 2. There was no statistically significant difference in the marginal bone level between sinus perforated implants and non-perforated implants (P>0.05). 3. There was no statistically significant difference in cumulative survival rate according to the preoperative bone level (P>0.05). These results suggests that perforation of maxillary sinus may not affect implant success in posterior maxillae.

무선 센서 네트워크에서 확률적 투표 기반 여과 기법의 에너지 효율성을 위한 퍼지 로직 시스템 기반의 다음 이웃 노드 선택 기법

이재관,남수만,조대호,Lee, Jae Kwan,Nam, Su Man,Cho, Tae Ho 한국시뮬레이션학회 2014 한국시뮬레이션학회 논문지 Vol.23 No.2

무선 센서 네트워크에서 센서 노드들은 개방된 환경에 배치되기 때문에 공격자들을 통해 쉽게 훼손된다. 공격자는 훼손된 노드를 통해 허위 보고서 및 허위 투표 주입 공격을 할 수 있다. 이러한 공격은 센서 노드의 에너지를 고갈시키거나 정상 보고서의 전송을 막는다. 이 두 가지 공격에 대응하기 위해 Li와 Wu는 확률적 투표 기반 여과 기법을 제안하였다. 이 기법은 보고서 임계값과 검증 노드를 고정적으로 사용하기 때문에 센서 노드의 에너지를 비효율적으로 사용한다. 본 논문에서는 PVFS의 에너지 향상을 위해 퍼지 로직 시스템을 기반으로 다음 이웃 노드 선택 방법을 제안한다. 퍼지 로직 시스템의 매개변수들은 에너지, 홉의 수, 검증 성공 횟수이며, CH는 퍼지 로직 시스템을 기반으로 도출된 2개의 이웃 노드 중에서 상태 정보가 높은 다음 이웃 노드를 선택한다. 실험을 통해 제안 기법은 기존 기법과 비교하여 약 9%의 에너지가 향상되었고, 센서 노드들의 에너지 절감을 통해 전체 네트워크의 수명 연장을 기대한다. Sensor nodes are easily compromised by attacker when which are divided in open environment. The attacker may inject false report and false vote attack through compromised sensor node. These attacks interrupt to transmission legitimate report or the energy of sensor node is exhausted. PVFS are proposed by Li and Wu for countermeasure in two attacks. The scheme use inefficiency to energy of sensor node as fixed report threshold and verification node. In this paper, our propose the next neighbor node selection scheme based on fuzzy logic system for energy improvement of PVFS. The parameter of fuzzy logic system are energy, hops, verification success count, CH select high the next neighbor node among neighbor nodes of two as deduction based on fuzzy logic system. In the experimental, our proposed scheme was improvement to energy of about 9% compare to PVFS.

最近 8年間 航空檢疫 實積 分析 및 '97年度 政策 運用方案

李在寬(Jae-Kwan Lee) 한국항공우주의학협회 1997 항공우주의학회지 Vol.7 No.2

확률적 투표기반 여과기법에서 가변적 환경을 위한 퍼지 기반 검증 노드 결정 기법

이재관(Jae-Kwan Lee),남수만(Su-Man Nam),조대호(Tae-Ho Cho) 한국컴퓨터정보학회 2013 한국컴퓨터정보학회 학술발표논문집 Vol.21 No.2

무선 센서 네트워크는 개방된 환경에서 무작위로 배치되어 악의적인 공격자들에게 쉽게 노출된다. 센서 노드는 한정된 에너지 자원과 손쉽게 훼손된다는 단점을 통해 허위 보고서와 투표 삽입 공격이 발생한다. Li와 Wu는 두 공격을 대응하기 위해 확률적 투표기반 여과기법을 제안하였다. 확률적 투표기반 여과기법은 고정적인 검증 경로를 결정하기 때문에 특정 노드의 에너지 자원고갈 위험이 있다. 본 논문에서는 센서 네트워크에서 보고서 여과 확률 향상을 위하여 퍼지 시스템을 기반으로 다음 노드 선택을 약 6% 효율적인 경로 선택 방법을 제안한다. 제안 기법은 전달 경로 상의 노드 중 상태정보가 높은 노드를 검증 노드로 선택하고, 선택된 검증 노드는 허용 범위 경계 값을 기준으로 공격 유형을 판별하고 여과한다. 실험결과를 통해 제안기법은 기존기법과 비교하였을 때 에너지 효율이 향상되었다.

수요응답형 버스 운영에 따른 농촌 지역 도로교통소음 및 소음노출인구 변화에 대한 평가

이재관(Jae Kwan Lee),유지수(Jisu Yoo),노창균(Chang-Gyun Roh),박재홍(Jaehong Park) 한국소음진동공학회 2024 한국소음진동공학회 논문집 Vol.34 No.2

Demand responsive transit (DRT) services, which are being introduced in rural areas because of the aging and continuous decline of the population, are anticipated to yield economic and environmental benefits through efficient bus operations. This study investigated the road traffic noise resulting from the altered routes of the DRT bus service that is in operation in Sangbuk-myeon, Yangsan-si. Before predicting the noise generated by the DRT bus service, the road traffic noise was measured and origin-destination data of the DRT buses in study area were collected. The road traffic noise was predicted along five bus routes and compared with the anticipated noise levels for conventional bus routes to analyze the areas and populations benefiting from noise reduction effects. Depending on the route setting of the bus, a noise reduction of up to 3.3 dB(A) was confirmed at the measurement point. Additionally, 4.6 % of Sangbuk-myeon residents experienced noise reduction effects in the range of 1 dB(A) ~ 3 dB(A). Based on these research results, it is expected that environmental quality and community welfare can be improved through the strategic planning and operation of DRT services in rural areas.

濁酒의 細菌汚染度 調査 硏究

李載寬(Jae Kwan Lee),鄭文植,李容旭 서울대학교 보건환경연구소 1972 보건학논집 Vol.9 No.2