• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.775-783
• /
• 2010

새마을 동차를 유지보수하는 용산기지의 이전에 따른 새마을 동차를 유지보수 할 기지가 없어, 현재 내구연한 20년인 새마을동차의 조기폐차가 논의 되고 있지만, 철도차량의 도입에 많은 비용이 소요되고, 정확한 정책판단이 요청되어 경제성 분석을 시행하였다. 분석을 위해 기존의 PP동차를 조기 폐차하는 경우와 신규간선형 EMU를 도입하는 경우, 철도차량정밀진단을 통해 PP동차를 내구연한을 초과하여 사용하는 경우를 시나리오 설정을 통해서 경제성분석을 시도하였다. 경제성 분석을 위해서 크게 유지보수비, 운영비, 차량감가상각비(차량 잔존가액)와 조기폐차에 따른 부대적인 비용을 산정하여 분석하였다. 특정한 철도공사의 사례이지만, 디젤차량과 전기차량의 운영비적인 측면에서 상세한 검토자료가 될 수 있다.

• 전기학회논문지
• /
• 제61권6호
• /
• pp.783-790
• /
• 2012

Electric Vehicles(EVs) and Plug-in Hybrid Electric Vehicles(PHEVs) which have the grid connection capability, represent an important power system issue of charging demands. Analyzing impacts EVs charging demands of the power system such as increased peak demands, developed by means of modeling a stochastic distribution of charging and a demand dispatch calculation. Optimization processes proposed to determine optimal demand distribution portions so that charging costs and demand can possibly be managed. In order to solve the problems due to increasing charging demand at the peak time, alternative electricity rate such as Time-of-Use(TOU) rate has been in effect since last year. The TOU rate would in practice change the tendencies of charging time at the peak time. Nevertheless, since it focus only minimizing costs of charging from owners of the EVs, loads would be concentrated at times which have a lowest charging rate and would form a new peak load. The purpose of this paper is that to suggest a scenario of load leveling for a power system operator side. In case study results, the vehicles as regular load with time constraints, battery charging patterns and changed daily demand in the charging areas are investigated and optimization results are analyzed regarding cost and operation aspects by determining optimal demand distribution portions.

• 한국군사과학기술학회지
• /
• 제16권1호
• /
• pp.5-26
• /
• 2013

Since the optimized use of sonar systems for target tracking is a practical problem for naval operations, the measure of mission achievability is needed for preparing efficient sonar-maneuver tactic. In order to quantify the mission achievability or Measure Of Effectiveness(MOE) for given sonar-maneuver tactics, we developed and tested a simulation algorithm. The proposed algorithm for tracking is based on Measure Of Performance(MOP) for localization and tracking system of sonar against target. Probability of Detection(PD) using steering beam patterns referenced to the aspect angle of sonar is presented to consider the tracking-performance of sonar. Also, the integrated software package, named as Optimal Acoustic Search Path Planning(OASPP) is used for generating sonar-maneuver patterns and vulnerability analysis for a given scenario. Through simulation of a simple case for which the intuitive solution is known, the proposed algorithm is verified.

• 한국철도학회논문집
• /
• 제10권1호
• /
• pp.16-21
• /
• 2007

Along with the opening of the high speed railroad in 2004, the number of long tunnels constructed is increasing and will be continued. In this respect, the fro inside the tunnels is a main cause of drastic damages to both facilities and lives of passengers on board, especially more severe consequences are expected if the fire occurs on a train in urban area. Even though, the threat to human lives due to the increasing number of tong tunnels and increasing train operation times inside such tunnels is getting bigger, the studies to measure safety of the tunnel and to enhance the safety of passengers have not been carried out enough in Korea. Therefore, in this paper, we will use the probabilistic method to predict the average number of deaths of passengers in case of fire on a train iii tunnel, and show the potential risk to passengers which can be a guide for safer design of tunnels to be constructed.

• 한국IT서비스학회:학술대회논문집
• /
• 한국IT서비스학회 2006년도 추계학술대회
• /
• pp.177-184
• /
• 2006

시스템의 동적 요소를 기술하고 분석하기 위해 C&C view 아키텍처를 주로 사용하지만 시스템의 실행 순서나 상태에 대한 정보가 부족하기 때문에 단지 C&C view 아키텍처로만 시스템의 동적 요소를 분석하기가 어렵다. FSP model은 시스템의 동작을 표현하기 위한 모델링 언어로써 시스템의 동작을 모델링 할 뿐만 아니라 LTSA라는 FSP 검증 툴을 이용하여 시스템의 특성을 자동으로 파악하기에도 용이한 특성을 가지고 있어 시스템 동적 요소 분석에 도움을 준다. 하지만 관련 정보를 얻기 어려워 FSP model을 구현하는데 어려움이 있다. 이 논문은 C&C view 아키텍처와 요구 사항(Use Case Scenario 혹은 Sequence diagram)을 근간으로 시스템의 동적 요소를 FSP로 모델링 하는 방법을 정의한다. 또한 LTSA 툴을 이용하여 자동적으로 시스템의 특성을 검증할 수 있고, 이를 통해 시스템 구현 전에 시스템의 에러를 찾아내고 해결하는 도움을 줄 수 있다. C&C view 아키텍처는 시스템의 컴포넌트와 커넥터에 대한 정보를 제공하여 주고 요구 사항은 소프트웨어 시스템의 행동에 대한 정보를 제공하여 줄 수 있다. 만약 우리가 컴포넌트와 커넥터에 대한 정보가 있고 시스템 동적 요소에 대해 알고 있다면 우리는 이것을 기반으로 메시지 흐름도를 구현할 수 있다. 메시지 흐름도는 Harel, Kugler 와 Pnueli에 의해 개발된 Synthesized 알고리즘을 이용하여 Statechart로 만들어지고 이것은 바로 FSP model로 변환될 수 있다. 우리가 소프트웨어 시스템에 대한 FSP model을 가지고 있다면 이것을 기반으로 시스템 행동 특성을 체크할 수 있으며 이는 향후 발생할 수 있는 결함을 미리 찾아내는데 유용한 도움이 될 수 있다. 우리는 간단한 예제를 통해 본 논문의 이론을 수립하였으며 이를 기반으로 실제 어플리케이션에 적용하여 그 효용성을 검증하였다.

• 동아시아경상학회지
• /
• 제12권1호
• /
• pp.35-42
• /
• 2024

Purpose: A railroad project is a complex system with large construction costs in the initial stage and ongoing operating costs over its lifecycle. Current railroad projects tend to be based on construction options, which leads to huge deficiencies in operating costs. This phenomenon results from a lack of appropriate tools to accurately estimate a railroad project's lifecycle costs. This study attempts to analyze the major components of railroad operating costs and to propose a decision-making system for analyzing the long-term lifecycle costs of railroad projects. Research design, data and methodology: We review the literature and analyze the current status of railroad operating costs in Korea and overseas. Based on previous projects, a framework for project options and operating costs is proposed. The framework is applied to actual railroad projects to demonstrate the validity of the model. Results: Case analysis shows that our framework is comprehensive in analyzing the primary aspects of railroad operating costs and plays an effective role in choosing various railroad project options. This study points out that the railway project operates inefficiently because estimating long-term costs without reflecting specific project options causes many errors. Conclusions: A major contribution of this study is the development of an improved framework for accurately estimating operating costs and providing policymakers and engineering firms with a holistic decision support system. Detailed components in estimating operating costs of the railroad business are discussed. And we present a decision-making tool that policymakers and private businesses can use in planning the railroad business.

• 디자인학연구
• /
• 제15권1호
• /
• pp.191-202
• /
• 2002

최근 다양한 가족유형이 일반화되어가면서 현재 웹상의 주거공간 설계에 대한 전반적인 재검토와 함께 다양하게 표출되는 사용자 요구에 충족할 수 있도록 새로운 형식의 주거 공간 리모델링 제안이 이루어져야 할 시점에 이르렀다. 이에 거주자 생활 패턴 변화에 대응하는 주거 공간의 제안과 웹 구조상치 설계 및 리모델링의 과정이 요구되고 있는 실정이다. 따라서 본 연구에서는 -인터넷 기반 가상아파트 리모델링 지능형 서비스 시스템- 사용 시나리오와 프로토타입을 제시하여 리모델링 자동 내역 산출을 위한 시뮬레이터 디자인을 연구하였다. 연구는 크게 네 부분으로 구성되어진다. 먼저, 문헌 연구를 통하여 리모델링의 범위 및 유형 분류로 가능하게 된, 전반적인 리모델링 개념과 기존 범람되어지고 있는 용어들을 정리하였다. 두 번째로 본 연구의 기본모델인 아파트의 공간 가변화를 고정 요소와 가변 요소로 분류하여 실제적 가변벽체의 적응성과 유연성을 살펴보았다. 세 번째로 현장 공사단계의 시뮬레이션을 위한 상담, 마감재, 가견적, 실견적의 데이터베이스화 과정이다. 그 데이터베이스는 다이아그램 계층구조와, 모델을 리모델링 할때 생성되는 일위대가 및 물량 산출 내역 근거표에 기초하여 소개되었다. 마지막으로 기 개발된 시스템을 활용하여 리모델링 시뮬레이터의 시스템 구조도와 사용 시나리오를 제시하였다. 그리고 그 시스템의 디자인 대안을 탐색하고 표현하기 위한 수단으로 프로토 타입을 제작하여 기존 온라인 프로그램 인터페이스의 효율성을 증가시키고 정보 누락의 문제점을 개선하였다.

• Journal of Ship and Ocean Technology
• /
• 제5권3호
• /
• pp.1-13
• /
• 2001

Present-day rules and regulations for the design and construction of ships are almost without exemption of a prescriptive and deterministic nature. Often it is argued that this situation is far from ideal; it does no right to the advances, which have been made during the past decades in engineering tools in marine technology, both in methodology and in computational power. Within IMO this has been realized for some time and has resulted in proposals to use Formal Safety Assessment(FSA) as a tool to improve and to modernize the rule making process. The present paper makes use of elements of the FSA methodology, but instead of working towards generic regulations or requirements, a Risk Assessment Approach, not unlike a 'safety case'; valid for a certain ship or type of ship is worked out. Delft University of Technology investigated the application of safely assessment procedures in ship design, in co-operation with Anthony Veder Shipowners and safety experts from Safely Service Center BV. The ship considered is a semi-pressurized-fully refrigerated LPG carrier. On the basis of the assumption that a major accident occurs, various accident, scenarios were considered and assessed, which would impair the safety of the carrier. In a so-called Risk Matrix, in which accident frequencies versus the consequence of the scenarios are depicted, the calculated risks all appeared lo be in the ALARP('as low as reasonable practicable') region. A number of design alternatives were compared, both on safety merits and cost-effectiveness. The experience gained with this scenario-based approach will be used to establish a set of general requirements for safety assessment techniques in ship design. In the view that assessment results will be most probably presented in a quasi-quantified manner, the requirements are concerned with uniformity of both the safety assessment. These requirements make it possible that valid comparison between various assessment studies can be made. Safety assessment, founded on these requirements, provides a validated and helpful source of data during the coming years, and provides naval architects and engineers with tools experience and data for safety assessment procedures in ship design. However a lot of effort has to be spent in order to make the methods applicable in day-to-day practice.

• 시스템엔지니어링학술지
• /
• 제12권1호
• /
• pp.73-87
• /
• 2016

Combining power generation and water production by desalination is economically advantageous. Most desalination projects use fossil fuels as an energy source, and thus contribute to increased levels of greenhouse gases. Environmental concerns have spurred researchers to find new sources of energy for desalination plants. The coupling of nuclear power production with desalination is one of the best options to achieve growth with lower environmental impact. In this paper, we will per-form a sensitivity study of coupling nuclear power to various combinations of desalination technology: {1} thermal (MSF [Multi-Stage Flashing], MED [Multi-Effect Distillation], and MED-TVC [Multi-Effect Distillation with Thermal Vapour Compression]); {2} membrane RO [Reverse Osmosis]; and {3} hybrid (MSF-RO [Multi-Stage Flashing & Reverse Osmosis] and MED-RO [Multi-Effect Distillation & Reverse Osmosis]). The Korean designed reactor plant, the APR1400 will be modeled as the energy production facility. The economical evaluation will then be executed using the computer program DEEP (Desalination Economic Evaluation Program) as developed by the IAEA. The program has capabilities to model several types of nuclear and fossil power plants, nuclear and fossil heat sources, and thermal distillation and membrane desalination technologies. The output of DEEP includes levelized water and power costs, breakdowns of cost components, energy consumption, and net saleable power for any selected option. In this study, we will examine the APR1400 coupled with a desalination power plant in the Kingdom of Saudi Arabia (KSA) as a prototypical example. The KSA currently has approximately 20% of the installed worldwide capacity for seawater desalination. Utilities such as power and water are constructed and run by the government. Per state practice, economic evaluation for these utilities do not consider or apply interest or carrying cost. Therefore, in this paper the evaluation results will be based on two scenarios. The first one assumes the water utility is under direct government control and in this case the interest and discount rate will be set to zero. The second scenario will assume that the water utility is controlled by a private enterprise and in this case we will consider different values of interest and discount rates (4%, 8%, & 12%).

• 산업경영시스템학회지
• /
• 제43권2호
• /
• pp.1-13
• /
• 2020

There are several methods of peak-shaving, which reduces grid power demand, electricity bought from electricity utility, through lowering "demand spike" during On-Peak period. An optimization method using linear programming is proposed, which can be used to perform peak-shaving of grid power demand for grid-connected PV+ system. Proposed peak shaving method is based on the forecast data for electricity load and photovoltaic power generation. Results from proposed method are compared with those from On-Off and Real Time methods which do not need forecast data. The results also compared to those from ideal case, an optimization method which use measured data for forecast data, that is, error-free forecast data. To see the effects of forecast error 36 error scenarios are developed, which consider error types of forecast, nMAE (normalizes Mean Absolute Error) for photovoltaic power forecast and MAPE (Mean Absolute Percentage Error) for load demand forecast. And the effects of forecast error are investigated including critical error scenarios which provide worse results compared to those of other scenarios. It is shown that proposed peak shaving method are much better than On-Off and Real Time methods under almost all the scenario of forecast error. And it is also shown that the results from our method are not so bad compared to the ideal case using error-free forecast.