발전소 주변 표층퇴적물 내 중금속원소 분산 특성

이두호,전병열,이창복,김범수,Lee, Doo-Ho,Jeon, Byeong-Yeol,Lee, Chang-Bok,Kim, Bum-Soo 한국해양학회 1999 바다 Vol.4 No.1

발전소 가동에 따른 퇴적물내 중금속원소의 오염 가능성을 알아보기 위하여 삼천포화력발전소와 영광원자력 발전소 주변해역의 표층퇴적물을 대상으로 중금속 함량 분석을 실시하였으며 선정된 일부 퇴적물에 대해서는 화학적 존재형태를 파악하기 위해 연속추출분석을 실시하였다. 퇴적불 중의 금속원소 함량 분포는 대체적으로 평균입도에 의해 조절되고 있으며 탄산염 함량 및 유기불 함량에 의해서도 영향을 받고 있는 것으로 나타났다. 또한 화학적 존재형태별 분석에서도 Mn을 제외한 대부분의 중금속이 잔류상으로 존재하고 있어 인위적인 오염에 의해서라기 보다는 자연적인 분산에 의해 존재하고 있는 것으로 나타났다. In order to examine the degree of heavy metal pollutions around Samcheonpo and Youngkwang power plants, marine sediment samples were analyzed to determine heavy metal contents. Some of these sediment samples were also analyzed by using of a sequential extraction technique to know geochemical forms of the metals. The results showed that the spatial distribution of heavy metals coincided very well with those of mean grain size, carbonates and organic matters. The chemical speciation data using sequential extraction analysis also showed that a considerable amount of heavy metals except for Mn were bounded in the residual fraction, which mode of occurrence of heavy metals was generally interpreted as being the result of the lithogenic origin.

온도와 물성의 불확실성을 고려한 고무 마운트의 동특성 해석

이두호,황인성,Lee, Doo-Ho,Hwang, In-Sung 한국전산구조공학회 2011 한국전산구조공학회논문집 Vol.24 No.4

본 논문에서는 통계적인 방법을 이용하여 점탄성 제진재인 합성고무의 물성에 대한 변동성을 평가하는 방법을 제안하고 측정데이터를 이용하여 합성고무에 대한 평가를 수행하고 합성고무로 이루어진 고무 마운트에 대한 동특성 해석을 수행하였다. 고무 물성의 불확실성 인자로는 외기 온도의 변화와 실험 데이터의 오차 및 점탄성 물질모델의 오차를 고려하였다. 고무는 분수차 미분모델로 표현되었고, 온도의 영향은 비선형 이동계수모델을 도입하여 복소계수로 나타내어 동강성과 감쇠를 표현하였다. 이러한 물성모델을 바탕으로 고무에 대한 물성 실험데이터와 물성계수의 확률밀도함수 사이에 정의된 우도함수를 최대화하는 통계적 보정방법을 이용하여 물성모델의 물질계수들에 대한 변동성을 추정하였다. 합성고무로 이루어진 제진용 고무 마운트에 대하여 유한요소모델을 이용하여 동특성을 계산하였다. 동특성의 계산시 추정된 물성의 통계값을 적용하고 몬테카를로 해석을 통하여 동강성의 변동성을 살펴서 그 변동성이 매우 큼을 확인하였다. In this paper, a statistical calibration method is proposed in order to identify the variability of complex modulus for a rubber material due to operational temperature and experimental/model errors. To describe temperature- and frequency-dependent material properties, a fractional derivative model and a shift factor relationship are used. A likelihood function is defined as a product of the probability density functions where experimental values lie on the model. The variation of the fractional derivative model parameters is obtained by maximizing the likelihood function. Using the proposed method, the variability of a synthetic rubber material is estimated and applied to a rubber mount problem. The dynamic characteristics of the rubber mount are calculated using a finite element model of which material properties are sampled from Monte Carlo simulation. The calculated dynamic stiffnesses show very large variation.

전달함수합성법을 이용한 엔진마운트 시스템의 강성 최적설계

이두호(Doo-Ho Lee),황우석(Woo-Seok Hwang) 한국자동차공학회 2002 한국자동차공학회 지부 학술대회 논문집 Vol.2002 No.10

A general procedure for the parametric sensitivity analysis of vibro-acoustic problems has been presented using the multi-domain FRF-based substructuring formulation. For an acoustic-structural system sub-structured by multiple domains, the substructuring formulation gives the reaction forces on the interface boundaries, which are differentiated directly in order to obtain the design sensitivity formula of the reaction forces with respect to the design vector. As a practical application, the proposed method is applied to the optimization problem of the engine mount system, of which objective is to minimize the interior sound over the concerned rpm range. The design variables selected are the stiffness of the engine mounts and bushes. Plugging the gradient information calculated by the proposed method into nonlinear optimization software, it gives optimal stiffnesses through iterations. The optimized interior noise in the passenger car shows that the proposed design sensitivity formulation is efficient and accurate<br/>

일반휴가형 M/G/1 대기체계의 대기시간 2차 적률 유도를 위한 휴리스틱 방법의 확장

이두호(Doo Ho Lee) 대한산업공학회 2017 대한산업공학회지 Vol.43 No.4

방화대교 ARCH TRUSS 제작 및 시공 (2)

이두호(Doo Ho Lee) 한국강구조학회 2001 韓國鋼構造學會誌 Vol.13 No.3

Price Competition in Duopoly Multimedia Cloud Service Market

Doo Ho Lee(이두호) 한국콘텐츠학회 2019 한국콘텐츠학회논문지 Vol.19 No.4

최근 들어 다수의 클라우드 서비스 제공자가 클라우드 컴퓨팅 서비스를 제공함으로써 각 제공자는 더 많은 사용자를 확보하기 위해 치열한 경쟁을 벌이고 있다. 서비스 제공자별 컴퓨팅 자원의 구성 및 서비스 제공 부하가 다르기 때문에 사용자는 다양한 수준의 서비스 품질을 경험할 수 있다. 따라서 클라우드 서비스 시장에서 더 많은 사용자를 확보하여 수익을 최대화하기 위해서는 서비스 품질에 대한 가장 합리적인 가격을 결정하는 것이 매우 중요하다. 본 연구에서는 두 명의 서비스 제공자가 존재하는 멀티미디어 클라우드 서비스 시장에서 두 제공자 간 서비스 가격 경쟁에 대해 다룬다. 두 명의 클라우드 서비스 제공자가 최적의 가격을 결정하여 상호 경쟁하고 자신의 이익을 최대화할 수 있는 가격 산정 방법을 비협력 게임이론으로 설명한다. 이를 위해 멀티미디어 클라우드 서비스의 제공 프로세스를 대기행렬 시스템으로 모형화하고, 분석 결과를 바탕으로 복점 멀티미디어 클라우드 서비스 시장에서 가격 경쟁 문제를 제안한다. As an increasing number of cloud service providers begin to provide cloud computing services, they form a competitive market to compete for users. Due to different resource configurations and service workloads, users may observe different response times for their service requests and experience different levels of service quality. To compete for cloud users, it is crucial for each cloud service provider to determine an optimal price that best corresponds to their service qualities while also guaranteeing maximum profit. To achieve this goal, the underlying rationale and characteristics in this competitive market must be clarified. In this paper, we analyze price competition in the multimedia cloud service market with two service providers. We characterize the nature of non-cooperative games in a duopoly multimedia cloud service market with the goal of capturing how each cloud service provider determines its optimal price to compete with the other and maximize its own profit. To do this, we introduce a queueing model to characterize the service process in a multimedia cloud data center. Based on performance measures of the proposed queueing model, we suggest a price competition problem in a duopoly multimedia cloud service market. By solving this problem, we can obtain the optimal equilibrium prices.

A Recursive Relation of the Queue Length Moments in the Discrete-Time Geo/Geo/1 and Geo/Geo/1/B Queues

Doo Ho Lee(이두호) 한국경영과학회 2017 韓國經營科學會誌 Vol.42 No.4

This note presents the recursive relations of the queue length moments in the discrete-time Geo/Geo/1 queue and finite buffer Geo/Geo/1/B queue, respectively. With the local balance equations governing the system, we provide an alternative and simple approach to derive the queue length moments instead of taking the derivatives of the probability generating function.

이중투과체 및 VIP복합 단열재 적용 평판 집열기의 성능 향상에 대한 연구

이두호(Doo Ho Lee),장한빈(Han Bin Jang),김용학(Young Hak Kim),도규형(Kyu Hyung Do),이광섭(Kwang Seob Lee),류남진(Nam Jin Lyu) 대한설비공학회 2016 설비공학 논문집 Vol.28 No.11

The purpose of this research is to improve the thermal effiency of solar collector and to quantitatively analyze its performance. Solar thermal systems have been limited to water heating systems mainly using low-temperature range. However, through diverse developments, the application has been extended to medium- and high-temperature fields such as solar heating, solar air conditioning, and solar thermal industrial process. Among the diverse research, this research is specially focusing on enhancement of the thermal performance by minimizing the heat loss coefficient of flat plate solar collectors. In order to do it, a front-side glazing material and a back-side insulation material with high insulated structure is proposed and based on computational analysis, the performance of energy collecting volume of the proposed solar collector is analyzed. The research shows that the proposed structure has the excellent performance at medium- and high-temperature range. therefore, it is expected that the proposed structure can easily replace existing technologies.

Analysis of the M/G/1 Queue with the Randomized Maintenance Policy

Doo Ho Lee(이두호),Kyung Chul Chae(채경철) 한국경영과학회 2009 한국경영과학회 학술대회논문집 Vol.2009 No.10

In this paper, we consider the M/G/1 queue with the randomized maintenance policy. Whenever the busy period ends, the server stays on and waits for arriving customers with probability p or is turned off and requires the maintenance of a single server with probability q(=1-p). At the end of each maintenance, the server is turned on and waits for arriving customers. Using transform technique, the transformed distributions of the queue length and the sojourn time are obtained. Finally, some system characteristics of interest are derived.

옥상녹화 식생에 따른. 표면온도 변화에 대한 실험적 연구

이두호(Lee Doo-Ho),이응직(Lee Eung-Jik),김준희(Kim Jun-Hui),윤두영(Yoon Doo-Young) 한국태양에너지학회 2013 한국태양에너지학회 학술대회논문집 Vol.2013 No.11

World Energy Council(WEC) announced the report titled "World Energy Scenario", and predicted that fossil fuel will be used as the main energy source by 2050. At this point of time, the international oil price is edging up to 110 dollars a barrel. Many countries all around the world are focusing on increasing the proportion of new renewable energy and reducing the proportion of fossil fuel, for cutting down greenhouse gas. Therefore, Korea has implemented the target management system by introducing "the Fundamental Law for Low-Carbon Green Growth" in 2012, and started the greenhouse gas and energy target management system" for cutting down the domestic green house gas by2020. In this context, Seoul City has pushed forward with the green roof project in 69 public and private buildings by investing nearly five billion won in it last year. Therefore, this study aims to obtain data to use for selection of vegetation to apply to green roofs by analyzing the change of surface temperature caused by green roof in the buildings chosen for the green roof project which Seoul City is pushing ahead with.