• Transactions on Electrical and Electronic Materials
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• v.7 no.5
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• pp.252-256
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• 2006

When a partial discharge takes place at the stator of a generator, the electrical pulse will propagate along the stator bars and the capacitor chains formed by the end part of the stator winds. On the first path, the pulse propagates as a travel wave at slow speed. On the second path, the pulse propagates at quick speed. Based on the data of the experiments on a real 50 MW steam generator, the author has found the pulses can propagate by magnetic field of the stator winding. It was studied that how to locating the partial discharge by signals coming from the different paths, including the features of signals on the two paths at time domain and frequency domain, the measurement frequency rang of the signals, the blind area, the advantage and disadvantage of this method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.307-309
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• 2013

국내에서는 1975년부터 민방위 기본법을 재정하여 민방위 경보 서비스를 실시하고 있으며 인구 5천이상의 도심지역의 민방위 경보를 위해 중앙과 시도를 중심으로 구축된 민방위 경보시스템이 운영되고 있다. 그러나 기존 재난경보시설과의 연동이 부족함으로써 특히 도심지역에서는 건물로 인한 민방위 경보 사각지대가 발생하면서 민방위경보 수신의 한계를 갖게 되었다. 이에 본 본 논문에서는 도시 소음차단 방음시설이 잘된 도심지역의 대형빌딩이나 아파트 내부 등 옥내에서의 민방위경보 사각지대를 해소하는 방안을 중심으로 도심지역의 민방위경보 수신 커버리지를 확대하는 방안에 대해 고찰한다.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.106-107
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• 2005

Small vessels of less then 20 tonnage and leisure boats such as motor boats, sailing yachts, water motorcycle, etc have been excluded from the rules and regulations such as Marine Leisure Safety Act, Ship Act and Ship Safety Act for a long time in Korea. As a result, these small vessels and leisure boats have remained within the blind area of maritime safety and environment protection. Among these vessels and boats, some leisure boats such as motor boats of 20 horse power or more(excluding motor boats equipped with engine inside the vehicles), water motorcycles and rubber boats of 30 horse power or more are incorporated into the Marine Leisure Safety Act through the registry, safety inspection, insurance early 2005 in Korea. In relation to the scope of application of the national Acts concerned, I consider the conflicts between Acts and suggest the subordinate enforcement ordinance and regulations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.2
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• pp.82-95
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• 1992

It has been known that the application of an airflow window system reduces the energy consumption compared with conventional double pane window in a building. But how to analyze thermal load in a building with an airflow window system has not been well known. so two kinds of method (Mode 1 and Mode 2) to analyze time dependent thermal load of the building with an airflow window system are presented in this study. The results of load analysis about the model building(total area : $4521m^2$, 3 floors) by Mode 2 show that the maximum cooling and heating load in a building with an airflow window system are decreased about 12-17% and about 19.5% than with double pane glass window, and yearly energy consumption with an airflow window system is saved about about 20% than with double pane glass window.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3655-3673
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• 2014

Rendezvous is a process of two or more cognitive radio nodes gathering on the same channel at the same time for a negotiation to establish data communications. This paper discusses rendezvous issues in cognitive radio networks. It details why rendezvous is an issue in cognitive radio networks and how rendezvous works. It classifies channel access methods, and details sequence-based channel-hopping methods. It surveys existing works on blind rendezvous and compares the proposed algorithms in terms of the maximum time to rendezvous. This paper discusses the properties that an efficient channel-hopping rendezvous algorithm should have and illustrates common issues in the existing rendezvous methods. It also explains open research issues in the rendezvous area.

• Proceedings of the Safety Management and Science Conference
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• 2009.11a
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• pp.495-505
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• 2009

Unpaid Family Worker is blind area of industry safety. Danger of industrial accident is some high but because was excepted in industrial accident compensation insurance application. In most case, because paltry Unpaid Family Worker is no opportunity to take safety education to prevent industrial accidents and there are few safety facility and safety equipment, etc., among business, it may be said that probability to suffer industrial accidents on a trifling mistake or carelessness is higher than general worker of business. Consider such difficult actuality of Unpaid Family Worker and our country must give these benefit of industrial accident compensation insurance application, as opened the door of insurance application in recognition of worker position by "Industrial accident compensation insurance Law" to middle·smaller enterprise's business proprietor or special form labor employees.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.872-878
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• 2009

Passenger safety is a primary concern of the railway system. However, dozens of people are killed every year when they accidently fall on to the track from the boarding platform. This is one of the most urgent issues to solve regarding the railway platform. The installation environment, and the blind area problems as well as maintenance and operating costs which are not efficient have to be looked at. To solve these problems, we propose a 3D laser radar sensor based monitoring system for the railway platform. This paper introduces an overview, the detecting method, and the interface with the signalling system in detecting a fallen passenger from the platform using the 3D laser radar sensor.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.1
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• pp.63-69
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• 2017

This paper proposes a new device for a portable braille device using Atmega128 and solenoid magnets. This braille device is composed of three panels, and each panel has six solenoid dots. This device aims to help the disabled people who cannot communicate with others. As an application example, when a disabled people approach a traffic light, it sends a message via Bluetooth to the proposed device letting people recognize a dangerous area. The message converted from the database is based on standard braille chart.

• Bulletin of the Korean Chemical Society
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• v.14 no.2
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• pp.250-255
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• 1993

A dual capillary column system is described for the simultaneous analysis of a given sample and measurement of retention index (RI) and area ratio (AR) values of each peak on two capillary columns of different polarity, DB-5 & DB-1701 from a single injection. Both capillary columns were connected to either a splitless injector or an on-column injector via a deactivated fused-silica capillary tubing of 1 m length and a 'Y' splitter. Both injection modes allowed to measure RI and AR values with high reproducibility (<0.01% RSD) and high accuracy (<10% RE), respectively with the exception that the trace and high boiling solutes required the on-column mode for the accurate quantification and AR comparison. When the dual capillary column system in on-column injection mode was applied to the blind samples containing organic acids, each acid was positively indentified by the combined computer RI library search-AR comparison.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.142-149
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• 2003

Blind hydraulic backfilling is a commonly used technique for subsidence control of the strata over unapproachable waterlogged underground excavations. In this investigation model studies on all the three variants of this technique, namely, hydro-pneumatic or air-assisted gravity backfilling, pumped-slurry backfilling and simple gravity backfilling, have been carried out in fully transparent models of the underground excavations. On examination of the filling process, it was revealed that in all the three cases, the basic process of filling occurs by sand transport along one or more meandering channels. The relative influence of sand, water and air flow rates on the area of filling from a single inlet point and the hydraulic pressure loss per unit length were studied in details. In hydro-pneumatic backfilling process, the air bubbles while moving upward through the meandering channels provide an additional buoyant force over and above the available hydraulic head. In this way the area of filling from a single borehole may be quite large even at small flow rates of water. During actual field implementation the injected air, if not released completely from the rise side holes, may cause troubles by way of creating potholes on the surface. The pumped-slurry technique has shown its capability of filling a relatively larger area at faster rate, especially when high-volume, low-pressure method was selected. But simple gravity filling was also found to be equally effective method as slurry pumping, especially when flow rates were high. In the second and third method discussed above, examination of variations of injection pressure was also done and its relation with physical phenomenon was also attempted. Some empirical relationships were also developed using multivariate regression with a view to help the practicing engineers.