• Journal of Electrical Engineering and Technology
• /
• v.11 no.6
• /
• pp.1582-1589
• /
• 2016

In this paper the integration of Distributed Generation (DG) in radial distribution system is investigated by computing the optimal site and size of DG to be placed. An analytical expression based on equivalent current injection has been derived by utilizing topological structure of radial distribution system to find optimal size of DG to minimize losses. In the presented formulation, the optimal DG placement is obtained without repeatedly computing the load flow. The proposed formulation can be used to find the optimal size of all types of DGs namely Type-I, Type-II, Type-III and Type-IV DGs. The investigations are carried out on IEEE 33-bus and 69-bus radial distribution systems. The optimal DG placement results into reduction in active and reactive power losses and improvement in voltage profile of the buses.

• New & Renewable Energy
• /
• v.19 no.3
• /
• pp.1-12
• /
• 2023

This study aims to evaluate the optimal size of the hydrogen facility to be installed in a zero-energy district in terms of load matching and facility efficiency. A mismatch between energy generation and consumption is a common occurrence in zero-energy districts. This mismatch adversely effects the energy grid. However, using an energy carrier such as hydrogen can solve this problem. To determine the optimal size of hydrogen fuel cells to be used on-site, simulation of hydrogen installation is required at both district-and building- levels. Each case had four operating schedules. Therefore, we evaluated eight scenarios in terms of load matching, heat loss, and facility operational efficiency. The results indicate that district-level installation of hydrogen facilities enables more efficient energy use. Additionally, based on the proposed model, we can calculate the optimal size of the hydrogen facility.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.5
• /
• pp.427-436
• /
• 2015

This study aims to select an optimal site for the development of small-scaled artificial ground water recharge system with the purpose of 50ton/day pumping in dry season. First of all, the topography shape satisfying the numerous factors of a hydraulic model experiment is defined and an appropriate pumping efficiency is calculated through the model experiment of injection and pumping scenario. In next step, GIS(Geographic Information System) database are constructed by processing several geospatial data to explore the optimal site. In detail, watershed images are generated from DEM(Digital Elevation Model) with 5m cell size, which is set for the minimum area of the optimal site selection. Slope maps are made from DEM to determine the optimal hydraulic gradient to procure the proper aquifer undercurrent period. Finally, the suitable site for artificial recharge system is selected using an integration of overall data, such as an alluvial map, DEM, orthoimages, slope map, and watershed images.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.40 no.3
• /
• pp.195-206
• /
• 2022

The primary purpose of this study was to analyze assessment factors by identifying and prioritizing live fire shooting area requirements using the AHP (Analytic Hierarchy Process) technique. Derived assessment factors for candidate sites were divided into six categories. Of these, four categories (base-to-range distance, weapon danger area, range terrain, and size) were in the realm of physical geography while the remaining two (land use and proximity to habitation) fell under the general heading of human geography. A case study was also conducted to select several alternative firing ranges using derived factors. The optimal location was analyzed by evaluating the candidate site using each assessment factor. As a result, it was found that assessment factors applying to GIS (Geographic Information System) were able to effectively analyze a suitable location for relocation of the focal training facility, taking into consideration public-safety issues, training requirements, and residents' past and likely future complaints. Through this process, it can prevent the waste of time and effort in determining an optimal location for a live fire shooing range.

• Journal of the Korea Safety Management & Science
• /
• v.7 no.1
• /
• pp.159-166
• /
• 2005

It is not difficult to see the road repairing. There are many and various machines which crush road surface. The efficiency and power of the machine depend on crushing head-shape, crushing interval, crushing load, crushing stress, machine's dropping height and roller's kind. The objective of this study is to select the optimal model among ten models of crushing machine with constraints such as crushing depth, variation, and crushed particle size. And then this paper provides the valid theoretical base on selected model. The data for this study are chosen from the site of construction in Kangnung during three months (2004. 6. 1${\~}$2004. 8. 31). The provided methodology in this paper will be fruitful not only for the selection of crushing machine but also for the aspects of construction period, cost, work efficacy according to the condition from the various sites of construction.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.4
• /
• pp.571-579
• /
• 1990

A dynamic relocation algorithm for non-deterministic process graph in distributed computer systems is proposed. A method is represented for determining the optimal policy for processing a process tree. A general database query request is modelled by a process tree which represent a set of subprocesses together with their precedence relationship. The process allocation model is based on operating cost which is a function fo selection of site for processing operation, data reduction function and file size. By using expected values of parameters for non-deterministic process tree, the process graph and optimal policy that yield minimum operating cost are determined. As process is relocated according to threshold value and new information of parameters after the execution of low level process for non-deterministic process graph, the assigned state that approximate to optiaml solution is obtained. The proposed algorihtm is heuristic By performing algorithm for sample problems, it is shown that the proposed algorithm is good in obtaining optimal solution.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1318-1327
• /
• 2008

Geotechnical sites in urban areas may have embedded structures such as utility lines and underground concrete structures, which cause difficulties in site investigation. This study is a preliminary research to establish knowledge base for developing an optimal technique for site investigation in urban areas. Surface-wave method and resistivity survey, which are frequently adopted for non-destructive site-investigation for geotechnical sites, were investigated to characterize effects of adjacent structures. In case of surface wave method, patterns of wave propagation were investigated for typical sets of multi-layered geotechnical profiles by numerical simulation based on forward modeling theory and field experiments for small-size model tests and real-scale tests in the field. In case of resistivity survey, 3-D finite element analyses and field tests were performed to investigate effects of adjacent concrete structures. These theoretical and experimental researches for surface-wave method and resistivity survey resulted in establishing physical criteria to cause interference of adjacent structures in site investigation at urban areas.

• Journal of Navigation and Port Research
• /
• v.41 no.1
• /
• pp.17-24
• /
• 2017

This study uses Conjoint Analysis to study optimal port operations at the newly built International P assenger Terminal (IPT) at Inchon Port, Korea. The perceptions of users, operators, and the Incheon Port Authority are compared and analyzed. The results of user Conjoint Analysis showed that rent calculation method was the most important factor in the NIPT operation plan, followed by establishing automation and the size of the site area. For the Incheon Port Authority and operators, the rent calculation method turned out to be the most important factor for NIPT operation plans. It was followed by establishing automation and the site area. Utility results showed the "investment cost preservation method" to have the highest rent calculation utility, "yard automation" as the priority, and "43,000 pyeong-48,000 pyeong" as the optimal site area.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.804-811
• /
• 2015

The presence of responsive loads in the promising active distribution networks (ADNs) would definitely affect the power system problems such as distributed generations (DGs) studies. Hence, an optimal procedure is proposed herein which takes into account the simultaneous placement of DGs and smart meters (SMs) in ADNs. SMs are taken into consideration for the sake of successful implementing of demand response programs (DRPs) such as direct load control (DLC) with end-side consumers. Seeking to power loss minimization, the optimization procedure is tackled with genetic algorithm (GA) and tested thoroughly on 69-bus distribution test system. Different scenarios including variations in the number of DG units, adaptive power factor (APF) mode for DGs to support reactive power, and individual or simultaneous placing of DGs and SMs have been established and interrogated in depth. The obtained results certify the considerable effect of DRPs and APF mode in determining the optimal size and site of DGs to be connected in ADN resulting to the lowest value of power losses as well.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.196-203
• /
• 2022

The resource constrained scheduling problem (RCSP) constitutes one of the most challenging problems in Project Management, as it combines multiple parameters, contradicting objectives (project completion within certain deadlines, resource allocation within resource availability margins and with reduced fluctuations), strict constraints (precedence constraints between activities), while its complexity grows with the increase in the number of activities being executed. Due to the large solution space size, this work investigates the application of Genetic Algorithms to approximate the optimal resource alolocation and obtain optimal trade-offs between different project goals. This analysis uses the cost of exceeding the daily resource availability, the cost from the day-by-day resource movement in and out of the site and the cost for using resources day-by-day, to form the objective cost function. The model is applied in different case studies: 1 project consisting of 10 activities, 4 repetitive projects consisting of 40 activities in total and 16 repetitive projects consisting of 160 activities in total, in order to evaluate the effectiveness of the algorithm in different-size solution spaces and under alternative optimization criteria by examining the quality of the solution and the required computational time. The case studies 2 & 3 have been developed by building upon the recurrence of the unit/sub-project (10 activities), meaning that the initial problem is multiplied four and sixteen times respectively. The evaluation results indicate that the proposed model can efficiently provide reliable solutions with respect to the individual goals assigned in every case study regardless of the project scale.