• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권7호
• /
• pp.2476-2495
• /
• 2021

Model-based software architecture verification and test scenarios generation are becoming more and more important in the software industry. Based on the existing temporal graph grammar, this paper proposes a new formalization method of the context-sensitive graph grammar for aiming at UML activity diagrams, which is called the UML Activity Graph Grammar, or UAGG. In the UAGG, there are new definitions and parsing algorithms. The proposed mechanisms are able to not only check the structural correctness of the UML activity diagram but also automatically generate the test scenario according to user constraints. Finally, a case study is discussed to illustrate how the UAGG and its algorithms work.

• 전자통신동향분석
• /
• 제39권3호
• /
• pp.87-97
• /
• 2024

With the timeline released by ITU-R (Radiocommunication Sector of the International Telecommunication Union), research and development activities for the International Mobile Telecommunications for 2030 and beyond (IMT-2030) are now in full swing. We provide an overview of the general process of making global core specifications for next-generation mobile systems and summarize the ITU-R Recommendation of the IMT-2030 Framework. The ITU-R Recommendation focuses on IMT-2030 usage scenarios and related capabilities. The expectations of 3GPP (Third Generation Partnership Project) activities for the proposal of candidate IMT-2030 global core specifications to the ITU-R are also discussed. The launch of IMT-2030 for commercial purposes is expected to begin in 2030.

• Current Photovoltaic Research
• /
• 제8권1호
• /
• pp.39-43
• /
• 2020

In this study, we predict the generation of end-of-life photovoltaic modules when Feed in Tariff applied, in Republic of Korea. Based on the installation of photovoltaic modules, we prepared three different senarios in order to estimate the generation of end-of-life photovoltaic modules. The senarios are i) early worn-out, ii) mid worn-out and iii) late-worn out senario. We selected the mid worn-out senario to estimated the amount of end-of-life photovoltaic modules in this study. Establishment of the end-of-life module generation scenario predicted generation of end-of-life photovoltaic module, and forecasted generation amount of end-of-life module to which Feed in Tariff was applied in consideration of installed photovoltaic modules installed by Feed in Tariff support. The generation of Feed in Tariff-applied end-of-life modules increased from 2021 to 2025 compared to without Feed in Tariff, and since then, the Feed in Tariff-applied end-of-life modules were generated as waste modules during the relevant period (2021 ~ 2025).

• 에너지공학
• /
• 제25권3호
• /
• pp.136-148
• /
• 2016

본 논문은 최근 공표된 Post-2020 신기후체제의 국가적 대응에 따른 발전부문의 역할들을 시나리오로 설정하여 경제적 파급효과를 비교 분석 하였다. 이를 위해 제7차 전력수급기본계획에서 제시한 2030년 발전원별 추정 발전량에 IAEA에서 발표한 온실가스 배출계수를 적용하여 온실가스 배출량을 예측하여 발전부문에서 발생시키는 초과 배출량을 산정하였다. 초과 배출량 감축을 위해 세 가지 시나리오를 기반으로 하였으며, 이들은 원자력발전소로 대체, 신재생발전설비 확대, CCS 도입 등이다. 분석 결과 원자력 발전소 대체 시나리오가 배출량 감소 및 경제적인 측면에서 가장 긍정적인 결과를 보였다.

• 한국자동차공학회논문집
• /
• 제16권6호
• /
• pp.1-9
• /
• 2008

The current test methods are insufficient to evaluate and ensure the safety and reliability of vehicle system for all possible dynamic situation including the worst case such as rollover, spin-out and so on. Although the known NHTSA J-turn and Fish-hook steering maneuvers are applied for the vehicle performance assessment, they aren't enough to estimate other possible worst case scenarios. Therefore, it is crucial for us to verify the various worst cases including the existing severe steering maneuvers. This paper includes the procedure to search for other useful worst case based upon the existing worst case scenarios mentioned above and its application in simulation basis. The only human steering angle is selected as a design parameter here and optimized to maximize the index function to be expressed in terms of either roll angle or yaw rate. The obtained scenarios were enough to generate the worst case to meet NHTSA worst case definition (ex.2-inch wheel lift). Additionally, as an application, the worst case steering maneuver is acquired for the vehicle to operate with a simple ESP system. It has been concluded that the new procedure in this paper is adequate to create other feasible worst case scenarios for a vehicle system both with an intelligent safety control system and without it.

• 에너지공학
• /
• 제17권2호
• /
• pp.88-99
• /
• 2008

본 논문에서는 WADE Economic Model을 이용하여 분산형전원 구축 시나리오에 따른 우리나라 전력계통의 영향을 정량적으로 평가하였다. WADE Economic Mode 미래의 증가하는 전력수요량[kWh]을 충족시키기 위하여 고려대상기간 동안의 매 년도에 대한 판매전력량 부족분[kWh]을 산정하고 판매전력량 부족분[kWh] 만족시키기 위한 신설발전설비를 시나리오에 따라 CG(Centralized Generation)전원과 DE(Decentralized Energy)전원인 두 가지 그룹으로 조합하여 담당하게 된다. 이와 같이 산정된 미래의 신설설비계획[kW]및 발전량[kWh]을 근거로 발전설비 및 송배전설비 건설비[원], 설비운전유지비[원], 연료비[원], 환경비[원]를 계산하여 전력소매요금을 산정한다. 본 연구에서는 WADE Economic Mode의 적용을 위한 우리나라 실 데이터를 구축하고 이를 WADE Economic Model에 적용하여 우리나라 전력계통에 분산형전원을 투입 시 미치는 영향을 분석함으로서 향후 우리나라 전력수급기본계획의 수립에 필요한 유용한 정보를 도출하도록 하였다.

• 한국기후변화학회지
• /
• 제8권3호
• /
• pp.213-220
• /
• 2017

The purpose of this study is to analyze effects of Greenhouse Gas (GHG) emission reduction in district energy business mainly based on Combined Heat and Power (CHP) plants. Firstly this paper compares the actual carbon intensity of power production between conventional power plants and district energy plants. To allocate the GHG from CHP plants, two of different methods which were Alternative Generation Method and Power Bonus Method, have been investigated. The carbon intensity of power production in district energy plants ($0.43tonCO_2e/MWh$) was relatively lower than conventional gas-fired power plants ($0.52tonCO_2e/MWh$). Secondly we assessed the cost effectiveness of reduction by district energy sector compared to the other means using TIMES model method. We find that GHG marginal abatement cost of 'expand CHP' scenario (-$134/ton$CO_2$) is even below than renewable energy scenario such as photovoltaic power generation ($87/ton$CO_2$). Finally the GHG emission reduction potential was reviewed on the projected GHG emission emitted when the same amount of energy produced in combination of conventional power plants and individual boilers as substitution of district energy. It showed there were 10.1~41.8% of GHG emission reduction potential in district energy compared to the combination of conventional power plants and individual boilers.

• Journal of Positioning, Navigation, and Timing
• /
• 제8권4호
• /
• pp.153-164
• /
• 2019

This paper presents the development of an end-to-end numerical simulator for signal design of the next generation global navigation satellite system (GNSS). The GNSS services are an essential element of modern human life, becoming a core part of national infra-structure. Several countries are developing or modernizing their own positioning and timing system as their demand, and South Korea is also planning to develop a Korean Positioning System (KPS) based on its own technology, with the aim of operation in 2034. The developed simulator consists of three main units such as a signal generator, a channel unit, and a receiver. The signal generator is constructed based on the actual navigation satellite payload model. For channels, a simple Gaussian channel and land mobile satellite (LMS) multipath channel environments are implemented. A software receiver approach based on a commercial GNSS receiver model is employed. Through the simulator proposed in this paper, it is possible to simulate the entire transceiver chain process from signal generation to receiver processing including channel effect. Finally, numerical simulation results for a simple example scenario is analyzed. The use of the numerical signal simulator in this paper will be ideally suited to design a new navigation signal for the upcoming KPS by reducing the research and development efforts, tremendously.

• 한국군사과학기술학회지
• /
• 제13권6호
• /
• pp.951-957
• /
• 2010

An optimal path generation method considering the safety of UGV(Unmanned Ground Vehicle) is proposed and demonstrated through examples. Among various functions of UGV, real-time obstacle avoidance is a key issue to realize realistic scenario in FCS(Future Combat Systems). A two-dimensional narrow corridor environment is considered as a test field. For each step of UGV movement, two objectives are considered: One is to minimize the distance to the target and the other to maximize the distance to the nearest point of an obstacle. A weighted objective function is used in the optimization problem. Equality and inequality constraints are taken to secure the UGV's dynamics and safety. The weighting factors are controlled by a fuzzy controller which is constructed by a fuzzy rule set and membership functions. Simulations are performed for two cases. First the weighting factors are considered as constant values to understand the characteristics of the corresponding solutions and then as variables that are adjusted by the fuzzy controller. The results are satisfactory for realistic situations considered. The proposed optimal path generation with the fuzzy control is expected to be well applicable to real environment.

• 대한전기학회논문지:전력기술부문A
• /
• 제50권9호
• /
• pp.424-430
• /
• 2001

A multi-level optimal power flow(OPF) algorithm has been evolved from a simple two stage optimal Power flow algorithm for constrained power economic dispatch control. In the proposed algorithm, we consider various constraints such as ower balance, generation capacity, transmission line capacity, transmission losses, security equality, and security inequality constraints. The proposed algorithm consists of four stages. At the first stage, we solve the aggregated problem that is the crude classical economic dispatch problem without considering transmission losses. An initial solution is obtained by the aggregation concept in which the solution satisfies the power balance equations and generation capacity constraints. Then, after load flow analysis, the transmission losses of an initial generation setting are matched by the slack bus generator that produces power with the cheapest cost. At the second stage we consider transmission losses. Formulation of the second stage becomes classical economic dispatch problem involving the transmission losses, which are distributed to all generators. Once a feasible solution is obtained from the second stage, transmission capacity and other violations are checked and corrected locally and quickly at the third stage. The fourth stage fine tunes the solution of the third stage to reach a real minimum. The proposed approach speeds up the two stage optimization method to an average gain of 2.99 for IEEE 30, 57, and 118 bus systems and EPRI Scenario systems A through D testings.