• 한국컴퓨터정보학회논문지
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• 제20권6호
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• pp.43-50
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• 2015

In order to protect important information of smart phone from these security threats, this paper has studied a mechanism for protecting information from the leakage of various information and personal information stored in the smart phone. This paper has configured the basic protection scope for the information protection and applied real time encodement when new contents were created. Also, this paper has applied a security function so that the content of the protected scope can be managed and erased remotely in preparation for loss and burglary.

• 한국직업건강간호학회지
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• 제12권1호
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• pp.71-79
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• 2003

Purpose: The purpose of this study was to describe the status of maternity protection in the industries for the development of educational database used by occupational health nurses (OHNs). Method: 100 OHNs were purposively sampled and they were charged in the occupational health manager of their own industries. Data were collected by the postal mail, the response rate was 53.0%, and analysis rate was 43.0%. Result: The results were as follows; 1. Most of subjects responded there was the institutionalization of a special holiday for woman workers (97.7%) and 90 days maternity leave (95.4%). Otherwise, the numbers of industry were smaller in the case of providing the breast-feeding time, temporary rest from office for child raring, restriction of hazard job, night job, and over time. The application rates were lower than the rate of institutionalization of all maternity protection items. 2. There were significant differences in institutionalization of maternity protection by the activity of the trade union. And the numbers of the industry applying the maternity protection were significantly different by the area and the types of industry. 3. Most OHNs responded 17 subjects were needed to the maternity protection education for women workers. Conclusion: It would be needed to develop the maternity protection education database in base of the status of maternity protection in the industries and the need of maternity protection education. The role of OHNs for maternity protection was expected to activate.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1104-1111
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• 2014

The digital substations are being built based on the IEC 61850 network. The cooperation and protection of power system are becoming more intelligent and reliable in the environment of digital substation. This paper proposes a novel method to prevent the malfunction caused by the Transformer Magnetizing Inrush Current(TMIC) using the IEC 61850 based data sharing between the IEDs. To protect a main transformer, the current differential protection(87T) and over-current protection(50/51) are used generally. The 87T IED applies to the second harmonic blocking method to prevent the malfunction caused by the TMIC. However, the 50/51 IED may malfunction caused by the TMIC. To solve that problem, the proposed method uses a GOOSE inter-lock signal between two IEDs. The 87T IED transmits a blocking GOOSE signal to the 50/51 IED, when the TMIC is detected. The proposed method can make a cooperation of digital substation protection system more intelligent. To verify the performance of proposed method, this paper performs the real time test using the RTDS (Real Time Digital Simulator) test-bed. Using the RTDS, the power system transients are simulated, and the TMIC is generated. The performance of proposed method is verified in real-time using that actual current signals. The reaction of simulated power system responding to the operation of IEDs can be also confirmed.

• Steel and Composite Structures
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• 제16권2호
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• pp.117-133
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• 2014

Natural vibration of truss cable structures is analyzed based upon the general structural analysis software ANSYS, energy variational method and Rayleigh method, the calculated results of three methods are compared, from which the characteristics of free-vibration are obtained. Moreover, vertical seismic response analysis of truss cable structures is carried out via time-history method. Introducing three natural earthquake waves calculated the results including time-history curve of vertical maximal displacement, time-history curve of maximal internal force. Variation curve of maximal displacement of node along span, and variation curve of maximal internal force of member along span are presented. The results show the formulas of frequencies for truss cable structures obtained by energy variational method are of high accuracy. Furthermore, the maximal displacement and the maximal internal force occur near the 1/5 span point. These provide convenient and simple design method for practical engineering.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.736-740
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• 2004

In order to overcome the problems of simulation methods, the power system transient stability assessment method using critical fault clearing time functions has been developed. Using the above method, this paper has developed the new method which can assess accurately and efficiently the effects of control and protection systems on transient stability which is the most important characteristic to assess in power systems. At first, critical fault clearing time functions CCT(W:load) are defined by taking notice of the fact that transient stability is mainly controlled by fault clearing time and load. Next, the method to be enable to assess accurately and efficiently the effects of control and protection systems on transient stability has been newly developed by using the above functions. Finally, it has been applied to the effect assessment in the occurrence of a three-phase fault in a model power system. Results of application have been clarified its effectiveness.

• 전기학회논문지
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• 제56권11호
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• pp.1873-1878
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• 2007

Current differential relays may maloperate during magnetic inrush and over-excitation because a significant differential current is produced. To prevent maloperation, the relays adopt some harmonic components included in the differential current. The harmonic restraints may increase the security of a relay but cause the operating time delay of a relay when an internal fault occurs. Moreover, the operating time delay is more increased if a current transformer (CT) is saturated. This paper describes a current differential relaying algorithm for power transformer protection with a compensating algorithm for the secondary current of a CT. The comparative study was conducted with and without the compensating algorithm. The performance of the proposed algorithm was investigated when the measurement CT (C400) and the protection CT (C400) are used. The proposed algorithm can compensate the distorted current of a CT and thus reduce the operating time delay of the relay significantly for an internal fault with CT saturation.

• 가정과삶의질연구
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• 제22권5호
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• pp.293-302
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• 2004

This study investigated the internship experiences of female college students who have participated in consumer counseling programs. The factors that determine interns' counseling time and interns' level of satisfaction with the programs were examined. Major results of this study are summarized in the following. First, interns' time spent on counseling consumers was the longest for the program at the Korean Consumer Protection Board, followed by the programs at consumer agencies and firms. The time spent on counseling by interns was shorter when there was l) a larger number of employees; 2) a smaller proportion of female employees: 3) a larger number of counseling rooms and a higher the frequency of counseling at the agency; and 4) a lower evaluation on the work performance of the counseling agency and the employees. Second, the level of utilization of interns was the highest in consumer agencies, followed by the Korean Consumer Protection Board. When all employees were female and the evaluated level of work performance of the counseling agency and employees was high, the level of intern utilization was also high. Third, the evaluated level of work performance was the highest at the Korean Consumer Protection Board, and interns' satisfaction with the internship program was the highest with the consumer agencies and the Korean Consumer Protection Board. Fourth, interns were highly satisfied with the program when the level of intern utilization was high and the agency's operation was evaluated as good.

• 디지털융복합연구
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• 제12권1호
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• pp.229-239
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• 2014

스마트워크 기술은 재택근무나 스마트워크센터, 모바일 단말기 등을 활용하여 시간과 공간의 제약이 없는 유연한 근무 환경을 제공한다. 업무의 효율성을 높여주는 스마트워크 시스템에는 그 편리성만큼 여러 정보보호에 대한 위협이 존재한다. 따라서, 스마트워크 구축시에는 정보보호 대책을 적절하게 마련되도록 정보보호 감리를 수행하여야 한다. 본 논문에서는 스마트워크 환경 구축을 위해 실무 기술적 차원에서 정보보호 감리모형을 제안하였다. 정보 보호를 위해 터미널, 네트워크 및 서버 영역으로 분류하고, 전문 정보보호감리 점검항목을 도출하였다. 또한, 스마트워크 정보보호 감리시점을 수립하고 점검항목과 ISMS 통제분야를 매핑함으로써 보안성과 효율성을 동시에 향상시킬 수 있도록 감리모형을 제안하였다. 제안한 정보보호 감리영역 및 점검항목들이 스마트워크 정보보호 감리의 목적에 부합되는지를 검증하기 위해서 감리사 및 IT 업계 종사자를 대상으로 설문조사를 통하여 적합성을 검증하였으며, 13개의 점검항목에서 97% 수준으로 적합하다는 결론이 도출되었다.

• 한국추진공학회지
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• 제23권1호
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• pp.108-115
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• 2019

고온 고압의 연소가스로부터 구조물을 보호하는 탄성내열재는 재료 조성 및 열환경 조건에 따라 열반응에 차이를 보인다. 본 논문에서는 탄성내열재의 배합 환경 변화에 따른 열반응 특성을 비교하였다. 탄성내열재의 내열 성능 시험은 내열고무성능평가장치(TPREM)를 이용하였으며, 연소실 압력 1,000 psig에서 연소가스속도를 각각 20 m/s과 100 m/s로 시험하였다. 연소실 압력-시간 선도, 재료 내부 온도-시간 선도, 탄성내열재 시편의 잔류 두께 및 열파괴두께를 획득하였다. 배합 환경에 따른 탄성내열재의 내열 성능은 유사하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.55-58
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• 1991

A generalization to the Digital Prolate Spheroidal Sequences is investigated, so that the Generalized Digital Prolate Spheroidal Sequences(GDPSS's) can be used as a powerful time window with many desirable properties. The GDPSS's in the form of the time window has 3 parameters with which we can control the shape of the window freely. Hence, GDPSS's can be used as the very useful time windows especially for digital distance protection.