• Journal of Korea Multimedia Society
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• v.20 no.8
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• pp.1369-1378
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• 2017

Pub/Sub (Publish/Subscribe) paradigm is a simple and easy to use model for interconnecting applications in a distributed environment. In general, subscribers register their interests in a topic or a pattern of events and then asynchronously receive events matching their interest, regardless of the events' publisher. In order to build a low latency lightweight pub/sub system for Internet of Things (IoT) services, we propose a GQSFPS (Group Quorum System-based Fog Pub/Sub) system that is a core component in the event-driven service oriented architecture framework for IoT services. The GQSFPS organizes multiple installed pub/sub brokers in the fog servers into a group quorum based P2P (peer-to-peer) topology for the efficient searching and the low latency accessing of events. Therefore, the events of IoT are cached on the basis of group quorum, and the delay-sensitive IoT applications of edge devices can effectively access the cached events from group quorum fog servers in low latency. The performance of the proposed GQSFPS is evaluated through an analytical model, and is compared to the GQPS (grid quorum-based pud/sub system).

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.8
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• pp.773-782
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• 2016

Recently, Energy Industry is in the face of such sustained Low-Growth, Energy Depletion, Climate Warming and Energy Companies bankruptcy, Various methods have been tried to break through it. In this paper, We propose Business Model of Energy New Industry in Electric Power Market after analyze background of Energy New Industry and Technology Trends. The proposed Business Model introduces Energy of Things(: EoT) Service based Advanced Metering Infrastructure, Energy Storage System(: ESS) for Frequency Regulation, Energy Prosumer using Vehicle and Grid(: VnG) and Smart City.

• Journal of the Korean Society of Food Culture
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• v.17 no.1
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• pp.49-56
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• 2002

The purpose of this study was to analyze staff satisfaction with staff foodservice in hospitals. The study compared the hospital staff's expectations and perceptions of foodservice. The quality satisfaction values were indicated as the differences between their expectations and perceptions. The subjects were 643 hospital staff in 11 Daegu . Kyungpook hospitals. Written questionnaires were used to collect the data. The completion rate was 76.9%. There were 17 attributes for foodservice quality, which were divided by factor analysis into four main quality factors; sensory, nutrition, sanitation and service. The high expectation and low perception items on the expectation and perception grid were: seasoning of the meals, taste of the meals, variety of the menu, nutritional considerations, cleanliness of the dishes, and prompt handling of meal complaints. On all the attributes measured, expectations were higher than perceptions. The quality satisfaction values were all negative. There were highly significant(p<0.001) correlations between quality satisfaction and variety of the menu(r=0.783), nutritional considerations(r=0.770), prompt dealing with meal complaints(r=0.762), cleanliness of meals(r=0.689), and courtesy of employees (r=0.653). There is a need to improve taste, menu variety, nutrition, sanitation, speed of handling meal complaints, and courtesy.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1269-1275
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• 2013

Recently, many studies have suggested that an electric vehicle (EV) is one of the means for increasing the reliability of power systems in new energy environments. EVs can make a contribution to improving reliability by providing frequency regulation in power systems in which the Vehicle-to-Grid (V2G) technology has been implemented and, if economically viable, can be helpful in increasing power system reliability. This paper presents a stochastic method for optimal coordination of charging and frequency regulation decisions for an EV aggregator using the Least Square Monte-Carlo (LSMC) with modeling of electricity price uncertainty. The LSMC can be used to assess the value of options based on electricity price uncertainty in order to simultaneously optimize the scheduling of EV charging and regulation service for the EV aggregator. The results of a numerical example show that the proposed method can significantly improve the expected profits of an EV aggregator.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.5
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• pp.81-90
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• 2007

Watershed topographical information is required in hydrologic analysis, supporting efficient hydrologic model operation and managing water resources. Watershed topographical data extraction systems based on desktop GIS are abundant these days placing burdens for spatial data processing on users. This paper describes development of a Web-based Geographic Information Systems that can delineate the Geum River sub-basins and extract watershed topographical data in real time. Through this system, users can obtain a watershed boundary by selecting outlet location and then extracting topographical data including watershed area, boundary length, average altitude, slope distribution about the elevation range with Web browsers. Moreover, the system provides watershed hydrological data including land use, soil types, soil drainage conditions, and NRCS(Natural Resources Conservation Service) curve number for hydrologic model operation through grid overlay technique. The system operability was evaluated with the hydrological data of WAMIS(Water Management Information System) with the government operation Web site as reference data.

• Structural Monitoring and Maintenance
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• v.7 no.3
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• pp.261-281
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• 2020

Civil structures may experience progressive deterioration and damage under environmental and operational conditions over their service life. Finite element (FE) model updating method is one of the most important approaches for damage identification in structures due to its capabilities in structural health monitoring. Although various damage detection approaches have been investigated on structures, there are limited studies on large-sized space structures. Thus, this paper aims to investigate the applicability and efficiency of sensitivity-based FE model updating framework for damage identification in large space structures from a distinct point of view. This framework facilitates modeling and model updating in large and geometric complicated space structures. Considering sensitivity-based FE model updating and vibration measurements, the discrepancy between acceleration response data in real damaged structure and hypothetical damaged structure have been minimized through adjusting the updating parameters. The feasibility and efficiency of the above-mentioned approach for damage identification has finally been demonstrated with two numerical examples: a flat double layer grid and a double layer diamatic dome. According to the results, this method can detect, localize, and quantify damages in large-scaled space structures very accurately which is robust to noisy data. Also, requiring a remarkably small number of iterations to converge, typically less than four, demonstrates the computational efficiency of this method.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.259-264
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• 2007

To efficiently utilize an e-Science application service which is built on a grid computing environment, it is vital to develop technologies for integrating each e-Science application services into a workflow and for executing the workflow on a cooperative environment. In this paper, we analyze the requirements of e-AIRS system, one of the e-Science environment of aerospace research community. From the requirement analysis, we propose the required functionality and the architecture of e-Science workbench for effective utilization of e-Science services on cooperative environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2276-2283
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• 2010

This study investigated the needs of u-City related civil servants upon guideline which is constituted for efficient promotion of the u-City IT infra construction. It utilized explanatory design in mixed method as a research design. In the research result, respondents needed as follows : 1)law and institutions involved in construction processes, 2)information about engineering techniques with general terms in u-City constructions, 3)reference service models. It proposed implications of constructing the new guideline based upon research results.

• Journal of the Korean Society of Safety
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• v.31 no.2
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• pp.10-17
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• 2016

The purpose of this paper is to deduct components that are in the group of highest risk(top 10%). the group is conducted for classification into groups by values according to risk priority through risk priority number(RPN) of FMEA(Failure modes and effects analysis) sheet. Top 10% of failure mode among total potential failure modes(72 failure modes) of ESS included 5 BMS(battery included) failure modes, 1 invert failure mode, and 1 cable connectors failure mode in which BMS was highest. This is because ESS is connected to module, try, and lack in the battery part as an assembly of electronic information communication and is managed. BMS is mainly composed of the battery module and communication module. There is a junction box and numerous connectors that connect these two in which failure occurs most in the connector part and module itself. Finally, this paper proposes RPN by each step from the starting step of ESS design to installation and operation. Blackouts and electrical disasters can be prevented beforehand by managing and removing the deducted risk factors in prior.

• KIEAE Journal
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• v.15 no.2
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• pp.5-17
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• 2015

Purpose: The goal of this research is to identify the planning techniques of Smart Green City with Ubiquitous method and carbon-neutral city planning techniques and to induce the main planning techniques through the analysis of relative importance and practical adaptation. Method: First of all, eighteen planning techniques were derived and categorized into three organization systems and six sectors through literature review and FGI analysis considering the applicability of Ubiquitous service for carbon-neutral city planning techniques. Secondly, based on expert surveys and AHP analysis, the importance of Smart Green City planning techniques was evaluated. Thirdly, using case study, six cases related to Smart Green City were analyzed for the current status of application of planning techniques. Lastly, considering the importance of planning techniques and practical aspects, the characteristics of Smart Green City and its implication were estimated. Result: Energy, Resource and Waste and Transportation sector were identified as important sectors for Smart Green City. In addition, 'Construction of Smart Grid', 'System for Utilization of New & Renewable Energy', 'Smart Resource Circulation Management System', 'Establishment of Public Transportation Information System basis', 'Construction of Pedestrian / Bicycle oriented Road Environment' are essential planning techniques to create Smart Green City.