• Journal of the Korean housing association
• /
• v.26 no.6
• /
• pp.115-126
• /
• 2015

Using the 2013 Korea Housing Survey, this research analyzed factors influencing residential satisfaction of low-income households concerning the economic condition, satisfaction about interior and exterior environments in dwelling, recognition of housing welfare policy. The economic condition showed that if there are less living expenses and more ordinary income, it brought about more positive effects in the ownership of a detached house, row and multi-family house. Most variables about satisfaction with the interior environment in dwelling have a significant influence on a detached house, apartment, row and multi-family house. The following factors played a significant role: accessibility to commercial facilities, neighborhood relationship and natural environment in the satisfaction with the exterior environment in dwelling about most types. Specifically, from an institutional perspective of housing welfare policy, the effect of the housing expenses support and the intention about remodeling were factors influencing residential satisfaction in cheonsei and monthly rent, free of a detached house and free of an apartment. These results will utilize preliminary data to establish housing welfare policy for low-income households.

• Convergence Security Journal
• /
• v.11 no.6
• /
• pp.53-58
• /
• 2011

There is increasing use of common commercial operation system and standard PCs to control industrial production systems, and cyber security threat for industrial facilities have emerged as a serious problem. Now these network connected ICS(Industrial Control Systems) stand vulnerable to the same threats that the enterprise information systems have faced and they are exposed to malicious attacks. In particular Stuxnet is a computer worm targeting a specific industrial control system, such as a gas pipeline or power plant and in theory, being able to cause physical damage. In this paper we present an overview of the general configuration and cyber security threats of a SCADA and investigate the attack tree analysis to identify and assess security vulnerabilities in SCADA for the purpose of response to cyber attacks in advance.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.2
• /
• pp.279-285
• /
• 2012

Most national critical key infrastructure, such like electricity, nuclear power plant, and petroleum is run on SCADA (Supervisory Control And Data Acquisition) system as the closed network type. These systems have treated the open protocols like TCP/IP, and the commercial operating system, which due to gradually increasing dependence on IT(Information Technology) is a trend. Recently, concerns have been raised about the possibility of these facilities being attacked by cyber terrorists, hacking, or viruses. In this paper, the method to minimize threats and vulnerabilities is proposed, with the virtual honeynet system architecture and the attack detection algorithm, which can detect the unknown attack patterns of Zero-Day Attack are reviewed.

• Journal of Environmental Science International
• /
• v.12 no.2
• /
• pp.151-155
• /
• 2003

The resources conservation system is comprehended, making Taean-haean National Park a research material by applying the fact of landowning, designating an LOP and Korea and Japan's Natural Park Act. Following conclusions were obtained in this study; Most of land areas of the National Park are privately owned; Only a few have been designated as Natural Reservation, a core reserved area on LOP, and a sandy beach, a sand dune, a sand spit, a tidal flat, a wetland, etc are distributed in the natural environment area so they were exposed to development; As seen in most of coastal type of National Parks, 13 commercial beaches are established. The annual rush to the beaches appears in July and August; Sand dune areas that have to be managed in terms of conservation, are turned into beaches. Moreover, the collective facilities areas are randomly developed. So they fail to function originally; The current Natural Park Act has no systematic devices for conservation of the natural resources on the seashore or offshore.

• Geotechnical Engineering
• /
• v.10 no.1
• /
• pp.83-102
• /
• 1994

Design practice of the preloading method, which is one of the most used ground improvement methods, includes quite complicated problems, especially when the draining facilities such as rand drain piles are to be considered. But, such complicated problems can be easily handled once an expert system is developed. The expert system is an interactive computer program which has just succeeded in commercial application. It is a new field of CAE(computer aided engineering), which has developed on application of geotechnical problems in recent years In this study, the expert system which gives practical assistance to engineers is developed by building the knowledge base for the preloading method with vertical drains. In this study, an expert system is built by using CLIPS as a development tool. And the expert system is developed under the workstation environment using UNIX OS.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.7
• /
• pp.57-66
• /
• 2009

Microturbines system (MTS) are currently being deployed as small scale on-site distributed generators for microgrids and smart grids. In order to fully exploit DG potentialities, advanced integrated controls that include power electronics facilities, communication technologies and advanced modeling are required. Significant expectations are posed on gas microturbines that can be easily installed in large commercial and public buildings. Modeling, control, simulation of microturbine generator based distributed generation system in smart grid application of buildings for both grid-connected and islanding conditions are presented. It also incorporates modeling and simulation of MT with a speed control system of the MT-permanent magnet synchronous generator to keep the speed constant with load variation. Model and simulations are performed using MATLAB, Simulink and SimPowerSystem software package. The model is built from the dynamics of each part with their interconnections. This simplified model is a useful tool for studying the various operational aspects of MT and is also applicable with building cooling, heating and power (BCHP) systems

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.296-301
• /
• 2003

A study on the engineering design and numerical thermo-hydraulic analysis for KSTAR TF coil structure cooling system has been conducted. The numerical analyses have been done to verify the engineering design of cooling using the commercial code, FLUENT and in-house code for calculating helium properties which varies with cooling tube's heat transfer. Through the engineering design process based on the steady heat balance concepts, the circular stainless steel tube with inner diameter of 4 mm for TF coil has been selected as cooling tube. From normal operation mode analysis results, total 28 cooling tubes were finally chosen. Also, three dimensional cool down analysis for TF coil with designed cooling tube was satisfied with next three design criteria. First is cooling work termination within a month, second is maximum temperature difference within 50 K in TF coil structure and third is exit helium pressure above 2 bar. Consequently, these cool down scenario results can afford to adopt as operating scenario data when KSTAR facilities operate.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.3
• /
• pp.129-134
• /
• 2004

The Available Transfer Capability (ATC) is defined as the measure of the transfer capability remaining in the physical transmission network for further commercial activity above already committed uses. The ATC determination s related with Total Transfer Capability (TTC) and two reliability margins-Transmission Reliability Capability (TRM) and Capacity Benefit Margin(CBM) The TRM is the component of ATC that accounts for uncertainties and safety margins. Also the TRM is the amount of transmission capability necessary to ensure that the interconnected network is secure under a reasonable range of uncertainties in system conditions. The CBM is the translation of generator capacity reserve margin determined by the Load Serving Entities. This paper describes a method for determining the TTC and TRM to calculate the ATC in the Bulk power system (HL II). TTC and TRM are calculated using Power Transfer Distribution Factor (PTDF). PTDF is implemented to find generation quantifies without violating system security and to identify the most limiting facilities in determining the network’s TTC. Reactive power is also considered to more accurate TTC calculation. TRM is calculated by alternative cases. CBM is calculated by LOLE. This paper compares ATC and TRM using suggested PTDF with using CPF. The method is illustrated using the IEEE 24 bus RTS (MRTS) in case study.

• Ocean and Polar Research
• /
• v.31 no.3
• /
• pp.257-264
• /
• 2009

Seventeen females of the mud crab Scylla serrata, from the State of Kosrae, Micronesia, were transported to the Fisheries Resources Research Institute, Gyeongsangnam-do, in oxygen-filled plastic bags. After acclimatization to a $30^{\circ}C$ holding temperature, nine females were selected for seed production trials. Spawning was hastened using eyestalk ablations; however, this may not be required in commercialscale mud crab seed production. Primary spawning produced an average of 2.4 million hatched larvae, whereas secondary spawning produced 0.4 million. About 10 days elapsed between spawning and hatching and 30 days between hatching and crablet. Mass mortalities up to 90% were observed between stages zoea 1 and zoea 2 in every trial. The highest survival rate from zoea 1 to crablet was estimated at 0.25%. Most commercial shrimp hatcheries in Korea are equipped with almost all necessary facilities and could be converted easily to mud crab hatcheries, able to run three to four times per year using hatchery technologies developed for blue crabs and Chinese mitten crabs.

• The KSFM Journal of Fluid Machinery
• /
• v.17 no.2
• /
• pp.5-11
• /
• 2014

Small hydro power, among other renewable energy resources, has been evaluated to have enough development value because it is a clean, renewable and abundant energy resource. In addition, small hydro power has the advantage of low cost development by using existing facilities like sewage treatment plants, water works and similar resources. But in the case of small hydro power systems, there are problems with degraded operation efficiency of turbine due to changes in flow rates. In order to overcome this, variable speed control can be achieved by using the power rectifier and permanent magnetic synchronous generator(PMSG) as a possible method to respond to the changes in flow rates. In this study, a commercial ANSYS CFD code was used to analyze the performance of 10kW class propeller hydro turbine and to also investigate flow characteristics at variable flow rates and runner vane.