• Title/Summary/Keyword: Vehicle to grid

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Numerical Analysis on Turning and Yaw Checking Abilities of KCS in Calm Water a Based on Free-Running Simulations (가상 자유 항주를 이용한 KCS 선형의 정수 중 선회 및 변침 성능 해석)

  • Yang, Kyung-Kyu;Kim, Yoo-Chul;Kim, Kwang-Soo;Yeon, Seong Mo
    • Journal of the Society of Naval Architects of Korea
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    • v.59 no.1
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    • pp.1-8
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    • 2022
  • To understand physical phenomena of ship maneuvering deeply, a numerical study based on computational fluid dynamics is required. A computational method that can simulate the interaction between the ship hull, propeller, and rudder will provide informative local flows during ship maneuvering tests. The analysis of local flows can be applied to improve a physical model of ship maneuvering that has been widely used in maneuvering simulations. In this study, the numerical program named as WAVIS that has been developed for ship resistance and propulsion problems is extended to simulate ship maneuvering by free-running tests. The six degree-of-freedom of ship motion is implemented based on Euler angles and the overset technique is applied to treat the moving grid of ship hull and rudder. The propulsion force due to a propeller is calculated by a panel method that is based on the lifting-surface theory. The newly extended code is applied to simulate turning and zig-zag tests of KCS and the comparison with the available experimental data has been made.

Standardization to ensure Interoperability and Reliability of Campus Microgrid (캠퍼스 마이크로그리드의 상호운용성 및 신뢰성 확보를 위한 표준화)

  • Yoon, Yongho
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.2
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    • pp.277-282
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    • 2020
  • The construction of medium-and large-sized microgrid systems by unit area, which is being promoted worldwide, is being developed and expanded in the form of efficient operation of electric grids and independent operation in preparation for power emergencies. Therefore, for the development of the domestic electricity industry, it is urgent to analyze the current status and technology of relevant international standardization, and to make international standardization of domestic standard (draft) on the matters that need to be enacted and newly established. Campus microgrid implements smart grid element technologies such as Integrated Energy Management System(EMS), Distributed Power(DG), Energy Storage System(ESS), Demand Response(DR), and Electric Vehicle(EV) in a university campus. As a system that reduces energy use and improves energy use efficiency and energy independence, standardization is established to secure interoperability and reliability of such systems.

Specific Impulse Gain for KSLV-II with Combination of Dual Bell Nozzle and Expansion-Deflection Nozzle (듀얼 벨 노즐과 E-D 노즐을 결합한 한국형발사체의 비추력 증가)

  • Moon, Taeseok;Huh, Hwanil
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.1
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    • pp.16-27
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    • 2018
  • A basic numerical analysis was performed to confirm the possibility of combining a dual bell nozzle and an Expansion-Deflection(E-D) nozzle. The dual bell nozzle was designed based on the first-stage nozzle of the Korean Space Launch Vehicle that is being developed, and the E-D nozzle concept was applied to the dual bell nozzle. The inlet condition was analyzed by applying eight types of frozen flow analysis, and k-${\omega}$ SST was selected as the turbulence model. The number of optimal grids was obtained as 240,000 through the grid sensitivity analysis. As a result, it was confirmed that the transition altitude increased owing to over-expansion when the E-D nozzle concept was applied to the dual bell nozzle, and the specific impulse gain was obtained at high altitudes compared with the KSLV-II first-stage engine.

Development of Information Technology Infrastructures through Construction of Big Data Platform for Road Driving Environment Analysis (도로 주행환경 분석을 위한 빅데이터 플랫폼 구축 정보기술 인프라 개발)

  • Jung, In-taek;Chong, Kyu-soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.669-678
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    • 2018
  • This study developed information technology infrastructures for building a driving environment analysis platform using various big data, such as vehicle sensing data, public data, etc. First, a small platform server with a parallel structure for big data distribution processing was developed with H/W technology. Next, programs for big data collection/storage, processing/analysis, and information visualization were developed with S/W technology. The collection S/W was developed as a collection interface using Kafka, Flume, and Sqoop. The storage S/W was developed to be divided into a Hadoop distributed file system and Cassandra DB according to the utilization of data. Processing S/W was developed for spatial unit matching and time interval interpolation/aggregation of the collected data by applying the grid index method. An analysis S/W was developed as an analytical tool based on the Zeppelin notebook for the application and evaluation of a development algorithm. Finally, Information Visualization S/W was developed as a Web GIS engine program for providing various driving environment information and visualization. As a result of the performance evaluation, the number of executors, the optimal memory capacity, and number of cores for the development server were derived, and the computation performance was superior to that of the other cloud computing.

Study for Effective Cooling of Ni-MH Battery Module Using Forced Air Flow (공기 유동에 따른 Ni-MH 배터리 모듈의 효과적인 냉각에 관한 연구)

  • Ahn, Chi-Yeong;Kim, Tae-Sin;Kim, Jun-Bom
    • Journal of the Korean Electrochemical Society
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    • v.14 no.4
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    • pp.253-260
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    • 2011
  • In this study, computational simulation was performed for thermal management of modules consisting of 10 batteries. Simplified structure and equivalent thermal resistance network was applied to maintain the thermal properties. Verification test of the mesh were in progress to ensure the reliability of 2.6 mm in the narrow gap between the battery, resulting in at least three divided mesh between the shape of the grid was required. Type of air from rear of the module, type of air from top of the module and type of air from bottom of the module were applied and effective cooling methods are discussed based on the location of fan and air intake of the modules. Maximum temperature and temperature differences of modules that directly affect the performance of the module were compared, and also behavior of the fluid was confirmed by comparing the air flow. The best maximum temperature is shown type of air from bottom of the module to $40.27^{\circ}C$ and type of air from top of the module shows smallest temperature difference $0.73^{\circ}C$.

An Adaptive Control of Smart Appliances with Peak Shaving Considering EV Penetration (전기자동차 침투율을 고려한 피크 부하 저감용 스마트 기기의 적응적 제어)

  • Haider, Zunaib Maqsood;Malik, Farhan H.;Rafique, M. Kashif;Lee, Soon-Jeong;Kim, Jun-Hyeok;Mehmood, Khawaja Khalid;Khan, Saad Ullah;Kim, Chul-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.5
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    • pp.730-737
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    • 2016
  • Electric utilities may face new threats with increase in electric vehicles (EVs) in the personal automobile market. The peak demand will increase which may stress the distribution network equipment. The focus of this paper is on an adaptive control of smart household appliances by using an intelligent load management system (ILMS). The main objectives are to accomplish consumer needs and prevent overloading of power grid. The stress from the network is released by limiting the peak demand of a house when it exceeds a certain point. In the proposed strategy, for each smart appliance, the customers will set its order/rank according to their own preferences and then system will control the household loads intelligently for consumer reliability. The load order can be changed at any time by the customer. The difference between the set and actual value for each load's specific parameter will help the utility to estimate the acceptance of this intelligent load management system by the customers.

Reinforcement Learning Based Energy Control Method for Smart Energy Buildings Integrated with V2G Station (강화학습 기반 V2G Station 연계형 스마트 에너지 빌딩 전력 제어 기법)

  • Seok-Min Choi;Sun-Yong Kim
    • The Journal of the Korea institute of electronic communication sciences
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    • v.19 no.3
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    • pp.515-522
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    • 2024
  • Energy consumption is steadily increasing, and buildings in particular account for more than 20% of the total energy consumption around the world. As an effort to cost-effectively manage the energy consumption of buildings, many research groups have recently focused on Smart Building Energy Management Systems (BEMS), which are deepening the research depth by applying artificial intelligence(AI). In this paper, we propose a reinforcement learning-based energy control method for smart energy buildings integrated with V2G station, which aims to reduce the total energy cost of the building. The results of performance evaluation based on the energy consumption data measured in the real-world building shows that the proposed method can gradually reduce the total energy costs of the building as the learning process progresses.

Comparison of Topographic Surveying Results using a Fixed-wing and a Popular Rotary-wing Unmanned Aerial Vehicle (Drone) (고정익 무인항공기(드론)와 보급형 회전익 무인항공기를 이용한 지형측량 결과의 비교)

  • Lee, Sungjae;Choi, Yosoon
    • Tunnel and Underground Space
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    • v.26 no.1
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    • pp.24-31
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    • 2016
  • Recently, many studies have been conducted to use fixed-wing and rotary-wing unmanned aerial vehicles (UAVs, Drones) for topographic surveying in open-pit mines. Because the fixed-wing and rotary-wing UAVs have different characteristics such as flight height, speed, time and performance of mounted cameras, their results of topographic surveying at a same site need to be compared. This study selected a construction site in Yangsan-si, Gyeongsangnam-do, Korea as a study area and compared the topographic surveying results from a fixed-wing UAV (SenseFly eBee) and a popular rotary-wing UAV (DJI Phantom2 Vision+). As results of data processing for aerial photos taken from eBee and Phantom2 Vision+, orthomosaic images and digital surface models with about 4 cm grid spacing could be generated. Comparisons of the X, Y, Z-coordinates of 7 ground control points measured by differential global positioning system and those determined by eBee and Phantom2 Vision+ revealed that the root mean squared errors of X, Y, Z-coordinates were around 10 cm, respectively.

Development of Intelligent ATP System Using Genetic Algorithm (유전 알고리듬을 적용한 지능형 ATP 시스템 개발)

  • Kim, Tai-Young
    • Journal of Intelligence and Information Systems
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    • v.16 no.4
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    • pp.131-145
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    • 2010
  • The framework for making a coordinated decision for large-scale facilities has become an important issue in supply chain(SC) management research. The competitive business environment requires companies to continuously search for the ways to achieve high efficiency and lower operational costs. In the areas of production/distribution planning, many researchers and practitioners have developedand evaluated the deterministic models to coordinate important and interrelated logistic decisions such as capacity management, inventory allocation, and vehicle routing. They initially have investigated the various process of SC separately and later become more interested in such problems encompassing the whole SC system. The accurate quotation of ATP(Available-To-Promise) plays a very important role in enhancing customer satisfaction and fill rate maximization. The complexity for intelligent manufacturing system, which includes all the linkages among procurement, production, and distribution, makes the accurate quotation of ATP be a quite difficult job. In addition to, many researchers assumed ATP model with integer time. However, in industry practices, integer times are very rare and the model developed using integer times is therefore approximating the real system. Various alternative models for an ATP system with time lags have been developed and evaluated. In most cases, these models have assumed that the time lags are integer multiples of a unit time grid. However, integer time lags are very rare in practices, and therefore models developed using integer time lags only approximate real systems. The differences occurring by this approximation frequently result in significant accuracy degradations. To introduce the ATP model with time lags, we first introduce the dynamic production function. Hackman and Leachman's dynamic production function in initiated research directly related to the topic of this paper. They propose a modeling framework for a system with non-integer time lags and show how to apply the framework to a variety of systems including continues time series, manufacturing resource planning and critical path method. Their formulation requires no additional variables or constraints and is capable of representing real world systems more accurately. Previously, to cope with non-integer time lags, they usually model a concerned system either by rounding lags to the nearest integers or by subdividing the time grid to make the lags become integer multiples of the grid. But each approach has a critical weakness: the first approach underestimates, potentially leading to infeasibilities or overestimates lead times, potentially resulting in excessive work-inprocesses. The second approach drastically inflates the problem size. We consider an optimized ATP system with non-integer time lag in supply chain management. We focus on a worldwide headquarter, distribution centers, and manufacturing facilities are globally networked. We develop a mixed integer programming(MIP) model for ATP process, which has the definition of required data flow. The illustrative ATP module shows the proposed system is largely affected inSCM. The system we are concerned is composed of a multiple production facility with multiple products, multiple distribution centers and multiple customers. For the system, we consider an ATP scheduling and capacity allocationproblem. In this study, we proposed the model for the ATP system in SCM using the dynamic production function considering the non-integer time lags. The model is developed under the framework suitable for the non-integer lags and, therefore, is more accurate than the models we usually encounter. We developed intelligent ATP System for this model using genetic algorithm. We focus on a capacitated production planning and capacity allocation problem, develop a mixed integer programming model, and propose an efficient heuristic procedure using an evolutionary system to solve it efficiently. This method makes it possible for the population to reach the approximate solution easily. Moreover, we designed and utilized a representation scheme that allows the proposed models to represent real variables. The proposed regeneration procedures, which evaluate each infeasible chromosome, makes the solutions converge to the optimum quickly.

Estimate and Analysis of Planetary Boundary Layer Height (PBLH) using a Mobile Lidar Vehicle system (이동형 차량탑재 라이다 시스템을 활용한 경계층고도 산출 및 분석)

  • Nam, Hyoung-Gu;Choi, Won;Kim, Yoo-Jun;Shim, Jae-Kwan;Choi, Byoung-Choel;Kim, Byung-Gon
    • Korean Journal of Remote Sensing
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    • v.32 no.3
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    • pp.307-321
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    • 2016
  • Planetary Boundary Layer Height (PBLH) is a major input parameter for weather forecasting and atmosphere diffusion models. In order to estimate the sub-grid scale variability of PBLH, we need to monitor PBLH data with high spatio-temporal resolution. Accordingly, we introduce a LIdar observation VEhicle (LIVE), and analyze PBLH derived from the lidar loaded in LIVE. PBLH estimated from LIVE shows high correlations with those estimated from both WRF model ($R^2=0.68$) and radiosonde ($R^2=0.72$). However, PBLH from lidar tend to be overestimated in comparison with those from both WRF and radiosonde because lidar appears to detect height of Residual Layer (RL) as PBLH which is overall below near the overlap height (< 300 m). PBLH from lidar with 10 min time resolution shows typical diurnal variation since it grows up after sunrise and reaches the maximum after 2 hours of sun culmination. The average growth rate of PBLH during the analysis period (2014/06/26 ~ 30) is 1.79 (-2.9 ~ 5.7) m $min^{-1}$. In addition, the lidar signal measured from moving LIVE shows that there is very low noise in comparison with that from the stationary observation. The PBLH from LIVE is 1065 m, similar to the value (1150 m) derived from the radiosonde launched at Sokcho. This study suggests that LIVE can observe continuous and reliable PBLH with high resolution in both stationary and mobile systems.