• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.264-270
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• 1998

This research broadens the prime concern of nuclear power plant operations from safe performance to both economic and safe performance. First emergency diesel generator is identified as one of main contributors for the lost plant availability through the review of plants forced outage records. The framework of an integrated architecture for performing modern on-line condition for operational availability improvement is configured in this work. For the development of the comprehensive sensor networks for complex target systems, an integrated methodology incorporating a structural hierarchy, a functional hierarchy, and a fault-system matrix is formulated. The second part of our research is development of intelligent diagnosis and maintenance advisory system, which employs Bayesian Belief networks (BBNs) as a high level reasoning tool incorporating inherent uncertainty use in probabilistic inference. Our prototype diagnosis algorithms are represented explicitly through topological symbols and links between them in a causal direction. As new evidence from sensor network development is entered into the model especially, our advisory of system provides operational advice concerning both availability and safety, so that the operator is able to determine the likely modes, diagnose the system state, locate root causes, and take the most advantageous action. Thereby, this advice improves operational availability

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.49-56
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• 2012

The purpose of this paper is to present a model for operating an emergency power system(EPS) that can secure a sufficient power supply used in case of a fire by analyzing the status of power supplies for emergency and firefighting operations. Investigations on the one of the causes of the operational failure of firefighting systems show evidence of EPS. Generally, when power to a building is interrupted, EPS supplies the emergency load(excepted firefighting load) first. When a power outage and a fire occur simultaneously, the EPS must be able to supply both the emergency load and the firefighting load, especially the firefighting load to the end. However, in order to save construction costs, emergency power generators in apartment, commercial, and business buildings can satisfy only one of the required loads. In cases like this, when a power outage and a fire occur simultaneously, there is a danger of firefighting equipment not operating due to insufficient power supply from the emergency generator. Therefore, an EPS must have a reserved firefighting power that can supply both the firefighting and the emergency load. Such EPS, when faced with a danger of an overload, will shut down the supply to all or part of the emergency load, thus securing a continuous power supply to the firefighting equipment. The generator power system with reserved firefighting power (RFP) will also have an indicator to show that the selective control is being used. General power generation systems for emergency load and firefighting load were found to have a demand factor of 50-60% with a lump. However, when installing an EPS, the builders must choose the higher demand factor suggested according to the official approval demand factor of the building.

• Journal of Advanced Navigation Technology
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• v.22 no.3
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• pp.189-197
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• 2018

In Korea, most of the land area is composed of mountainous areas, making it difficult to develop airports because there is not enough open space to operate airports or airfields. However, the current development of the air transportation industry and the rapid increase of aviation demand, the construction of the training airfield infrastructure should be more actively reviewed for safe and smooth flight training. In this study, we analyze the actual condition of operation of domestic training airfield and the case study of overseas training site in order to establish appropriate level standard model of training infrastructures. In addition, this study suggests implications for the appropriate scale and operational efficiency of the training flight infrastructure.

• Journal of Korean Society of Transportation
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• v.24 no.5 s.91
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• pp.109-121
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• 2006

The road should be designed in the consistent alignment which the driver can drive safely. Also, proper highway environments in order to maintain optimal operational speeds on highway sections should be provided In design stage, for highway environments, it is essential for an operational speed estimation model to different highway environments. If a method which could evaluate the status of the road safety is developed through this operational speed estimation model, it is possible to provide safe and more comfortable highways to road users. In the study factors to effect on operational speeds are classified into three groups horizontal & vertical alignments and traffic operation characteristic factors. Factors are chosen to effect on operational speeds by using collation analysis as classifications of tangent sections, horizontal curve sections and vertical curve sections. In order to develop operational speed estimation models in express highways, multi-regression analysis has been used in this study using the selected factors. This study has meaning that the developed estimation models for operational speeds and evaluation of degree of safety to horizontal and vortical alignments simultaneous. In order to represent whole area of the country with the developed models, the models should be re-analyzed with vast data related with road alignment factors in the near future.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.62-74
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• 2021

We compare Over-the-Tops (OTTs), Netflix and Amazon Prime Video (APV) with five success factors of innovation. Firstly, Netflix offers better personalized service than APV, because APV has collaborative filtering algorithms to recommend safe bets, not the customers really want. Secondly, APV' user interface is undercooked to lock the members in, even if it has more content and better price offer than Netflix retaining its loyal customers despite the price increase. Thirdly, Netflix has simple subscription model with three tiering, but APV has complicated pricing model having annual and monthly, APV and Prime Video (AV) app, Amazon subscription and extra payment of Amazon Prime Channels (APCs). Fourthly, Amazon has fewer partnership than Netflix especially when it comes to local TV series. Instead, Amazon has live TV channel collaboration including sports content. Lastly, both have strategic and operational agility in their organization well.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.87-96
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• 2007

Ubiquitous is a Latin-derived word meaning "to exist at any time and place" like water or air. In computing, the word "ubiquitous" indicates an environment in which users have access to networks without any limitation regarding computer networks or places. Important issues in building Ubiquitous Korea (U-Korea) are the social problems appearing with a rapid increase in the old age population. Nowadays, with the rise of the nuclear family, the increase in the number of elderly people living alone, and the change in the status of women, both wives and husbands are employed outside the home, and the relatives who would be responsible for supporting the elderly sometimes are on long or short business trips, and it happens that old people can't be looked after. Therefore the government developed a wireless paging system for the sick, disabled, old and weak so that when an emergency happens, by just simply dialing 119, an emergency aid center could take prompt action. However, the present wireless paging systems composing the under-layer of the emergency aid information system have some problems, such as, a lack of reliability, problems among terminals, mobile transmitters and receiving terminals, the users' refusal to admit the need for the system and poor operational skills, administrators' perfunctory management and checks, etc. On account of these problems, the system efficiency has degraded and therefore a system upgrade is necessary. In this paper, we attempt to evaluate the newly implemented SAFE119 system, a new wireless paging system seeking to correct the problems of the current system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.64-77
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• 2015

An effective method for produce munitions effectiveness data is to calculate weapon effectiveness indices in the US military's Joint Munitions Effectiveness Manuals (JMEM) and take advantage of the damage evaluation model (GFSM) and weapon Effectiveness Evaluation Model (Matrix Evaluator). However, a study about the Range Safety that can be applied in the live firing exercises is very insufficient in the case of ROK military. The Range Safety program is an element of the US Army Safety Program, and is the program responsible for developing policies and guidance to ensure the safe operation of live-fire ranges. The methodology of Weapon Danger Zone (WDZ) program is based on a combination of weapon modeling/simulation data and actual impact data. Also, each WDZ incorporates a probability distribution function which provides the information necessary to perform a quantitative risk assessment to evaluate the relative risk of an identified profile. A study of method to establish for K-Range Safety data is to develop manuals (pamphlet) will be a standard to ensure the effective and safe fire training at the ROK military education and training and environmental conditions. For example, WDZs are generated with the WDZ tool as part of the RMTK (Range Managers Tool Kit) package. The WDZ tool is a Geographic Information System-based application that is available to operational planners and range safety manager of Army and Marine Corps in both desktop and web-based versions. K-Range Safety Program based on US data is reflected in the Korean terrain by operating environments and training doctrine etc, and the range safety data are made. Thus, verification process on modified variables data is required. K-Range Safety rather than being produced by a single program, is an package safety activities and measures through weapon danger zone tool, SRP (The Sustainable Range Program), manuals, doctrine, terrain, climate, military defence M&S, weapon system development/operational test evaluation and analysis to continuously improving range safety zone. Distribution of this K-range safety pamphlet is available to Army users in electronic media only and is intended for the standing army and army reserve. Also publication and distribution to authorized users for marine corps commands are indicated in the table of allowances for publications. Therefore, this study proposes an efficient K-Range Safety Manual producing to calculate the danger zones that can be applied to the ROK military's live fire training by introducing of US Army weapons danger zone program and Range Safety Manual

• Advances in aircraft and spacecraft science
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• v.4 no.6
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• pp.651-677
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• 2017

For the past ten years' efforts have been made to introduce environmentally-friendly "green" electric-taxi and maneuvering airplane systems. The stated purpose of e-taxi systems is to reduce the taxiing fuel expenses, expedite pushback procedures, reduce gate congestion, reduce ground crew involvement, and reduce noise and air pollution levels at large airports. Airplane-based autonomous traction electric motors receive power from airplane's APU(s) possibly supplemented by onboard batteries. Using additional battery energy storages ads significant inert weight. Systems utilizing nose-gear traction alone are often traction-limited posing serious dispatch problems that could disrupt airport operations. Existing APU capacities are insufficient to deliver power for tractive taxiing while also providing for power off-takes. In order to perform comparative and objective analysis of taxi tractive requirements a "standard" taxiing cycle has been proposed. An analysis of reasonably expected tractive resistances has to account for steepest taxiway and runway slopes, taxiing into strong headwind, minimum required coasting speeds, and minimum acceptable acceleration requirements due to runway incursions issues. A mathematical model of tractive resistances was developed and was tested using six different production airplanes all at the maximum taxi/ramp weights. The model estimates the tractive force, energy, average and peak power requirements. It has been estimated that required maximum net tractive force should be 10% to 15% of the taxi weight for safe and expeditious airport movements. Hence, airplanes can be dispatched to move independently if the operational tractive taxi coefficient is 0.1 or higher.

• Strategy21
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• s.42
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• pp.258-292
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• 2017

This paper is designed to make a national strategic concept for the ROK's maritime security and to explore cooperation directions for the ROK Navy and Coast Guard in order to implement the newly-made maritime security strategic concept. As strategy is composed of three main categories(goals, ways, means), the goal of the ROK's maritime security strategy is 'Safe and Affluent Sea' and the way to realize the goal is the principle of cooperative leverage, and the means as tasks to implement the strategic concept are maritime safety, maritime security, and maritime stewardship. The concept of national fleet as used in the US is applied to promoting the cooperation between the ROK Navy and Coast Guard. Thus, under the newly-established maritime security strategic concept along with the national fleet model, followings are suggested as policy proposals for facilitating mutual cooperation between the ROK Navy and Coast Guard in dealing with not only traditional threats but also non-traditional treats at sea and from the sea as well. First, the ROK Navy and Coast Guard has been making efforts to enhance interoperability between the two sea services. However, the mutual cooperations have been focused mainly on areas on operational level rather than policy level. Therefore, the two sea services are recommended to enlarge exchanges and cooperation in policy areas. Second, there are still demands for further cooperation areas between the two sea services in command and communications. The interoperability in C2 between the two needs to be upgraded even to the areas of anti-terrorist activities ar sea, ASUW, ASW, maritime interdiction, etc. Third, mutual comparability between the two needs to be reflected in the maritime forces development to ensure the comparability in UNREP and other logistics areas. Fourth, the standardization of logistical materials and equipments is needed as a way of sustaining operational capability and logistical capacity for the ROK Navy and Coast Guard as well. Fifth, the ROK Navy and Coast Guard are recommended to participate more actively in international maritime cooperation activities such as PASSEX. Sixth, Complementary laws and regulations need further to be revised and to be newly made for collectively managing swiftly maritime accidents and natural disasters at sea.

• Advances in concrete construction
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• v.8 no.4
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• pp.269-276
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• 2019

The cracking and spalling caused by fracture of concrete lining have adverse impacts on serviceability and durability of the tunnel, and the subsequent maintenance work for damaged structure needs to be specific to the damaging causes. In this paper, a particular case study of an operational tunnel structure is presented for the serious cracking and spalling behaviours of concrete lining, focusing on the multi-factors inducing lining failure. An integrated field investigation is implemented to characterize the spatial distribution of damages and detailed site situations. According to results of nondestructive inspection, insufficient lining thickness and cavity behind lining are the coupled-inducement of lining failure bahaviors. To further understanding of the lining structure performance influenced by these multiple construction deficiencies, a reliable numerical simulation based on extended finite element method (XFEM) is performed by using the finite element software. The numerical model with 112 m longitudinal calculation, 100 m vertical calculation and 43 m vertical depth, and the concrete lining with 1450 solid elements are set enrichment shape function for the aim of simulating cracking behavior. The numerical simulation responses are essentially in accordance with the actual lining damaging forms, especially including a complete evolutionary process of lining spalling. This work demonstrates that the serious lining damaging behaviors are directly caused by a combination of insufficient thickness lining and cavity around the surrounding rocks. Ultimately, specific maintenance work is design based on the construction deficiencies, and that is confirmed as an efficient, time-saving and safe maintenance method in the operational railway tunnel.