• Journal of Advanced Marine Engineering and Technology
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• 제18권3호
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• pp.78-84
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• 1994

The location of periodic noises in phase of AC power wave reveals to be specific according to the noise kinds which can be generally classified into modulation and baseband types in DLC. The former noise type has constant noise phase which is originated from switching mode power supplies and the latter normally caused from thyristor circuit of low switching frequency is compared to be more dispersive than the other.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.157-160
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• 2003

ODMRP is protocol that support multicast and unicast in Ad-hoc network. When some one node must transmit data by unicast way in this ODMRP, must pass through periodic flooding process to find a path and overhead happens thereby. Our scheme stores the found path into the table in a unicast mode and, when the node sends data, it refers to the DR FG table so that reduces the traffic caused by control packets(JOIN QUERY, JOIN REPLY) of a receiver node, while source/destination nodes flood periodic control packets to look for a path in ODMRP. We present that our scheme is much more improved on the time of looking for a path than existing ODMRP methods by means of the simulation.

• 한국유체기계학회 논문집
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• 제2권1호
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• pp.81-87
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• 1999

This study presents the measurement techniques on the periodic fluctuating flow such as the discharge flow of a centrifugal impeller in an unstable operating region. During rotating stall, the flow at the exit of a centrifugal compressor impeller fluctuates periodically with a lower frequency than that of the blade passing. To observe the blade-to-blade flow characteristics during the rotating stall, the phases of all the sampled data sets should be adjusted to those of the reference signals with two processes, in these processes, DPLEAT (Double Phase-Locked Ensemble Averaging Technique) can be used. From these measurements and data processing techniques, the characteristics illustrated a blade-to-blade flow with high frequency, but also a periodic rotating stall flow with a low frequency at the centrifugal impeller exit which was clearly observed.

• 지역사회간호학회지
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• 제4권2호
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• pp.139-145
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• 1993

The purpose of this study was to identify the degree and the relationship of the Knowledge, Attitude and Practice of industrial health care services of workers. This information will provide useful data for an effective industrial health care service. The was collected from 600 data employees in Kwang-ju city & Chonnam province. The data was gathered by questionnaire from Dec 20, 1992 to Jan 20, 1993. The questionnaire was developed by the Academic Affairs of Community Health Nursing Academy. Data was analyzed by using the statistical computer package, SPSS to manipulate the data along with percentages, means, standard deviations, modes, t-test and ANOVA. The results in this study were summarized as follows: 1. General characteristics of workers: Distributions of workers was laborer(76.2%). in the 25-34 age group(50.2%), married(63.3%), males comprised(77.5%), the educational level with the highest percentage was high school graduates (71.1%), with a monthly income of 300-700 thousand won(43.8%), and has been working in the present career over seven years (31.5%). 2. The Knowledge, Attitude and Practice levels of employees about industrial health care services The levels were measured according to a five point scale. The total mean score of knowledge was 2.92 points out of 4. The following are the scores of Knowledge of special medical examination and location of industrial clinic(3.48), periodic medical examination (3.18), occupational disease(3.08), personal protective equipment (2.92), and health education(1.37). The total mean score of Attitude was 2.77 point out of 4. The following are the scores of Attitude in order of working environment (3.35), necessity of periodic medical examination and health education(3.15), the worker's perception influence on the working environment to health was high(3.11). But, the level of satisfaction in the content of periodic medical examination was low(2.19). The total mean score of Practice was 2.70 points out of 4. The scores of Practice in order were, practice of periodic medical examination(3.70), utilization of industrial clinic(2.92), and to participate in health education(1.47). 3. The relationship of general characteristics to Knowledge, Attitude, and Practice of workers: Knowledge had a significant difference by sex (P<.01), marital status(P<.01), education level (P<.05) and monthly income(P<.01). Attitude was significantly different with sex(P<.05) and Practice was significantly related to monthly income (P<.01).

• 한국의학물리학회지:의학물리
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• 제28권4호
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• pp.197-206
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• 2017

We develop guidelines for the quality assurance of radiation treatment planning systems (TPS) by comparing and reviewing recommendations from major countries and organizations, as well as by analyzing the AAPM, ESTRO, and IAEA TPS quality assurance guidelines. We establish quality assurance items for acceptance testing, commissioning, periodic testing, system management, and security, and propose methods to perform each item within acceptable standards. Acceptance includes tests of hardware and network environments, data transmission, software, and benchmarking as specified by the system supplier, and apply the IAEA classification criteria. Commissioning includes dosimetric and non-dosimetric items for assessing TPS performance by applying the AAPM classification criteria and the latest technical items from the IAEA. Periodic quality assurance tests include daily, weekly, monthly, yearly, and occasional items by applying the AAPM classification criteria. System management and security items include the state and network connectivity of TPS, periodic data backup, and data access security. The guidelines for TPS quality assurance proposed in this study will help to improve the safety and quality of radiotherapy by preventing incidents related to radiotherapy.

• 한국정보과학회논문지:정보통신
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• 제32권3호
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• pp.339-349
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• 2005

최근 수년 동안, 데이타 방송기술은 많은 수의 클라이언트를 갖는 이동 컴퓨팅 환경에서 매우 효과적인 데이타 전달 시스템으로 주목받고 있다. 특히 흔성 방송은 주기적인 반복 데이타 방송과 온디멘드 방송을 통해, 제한된 대역폭 상에서 많은 이동 클라이언트를 수용하면서 동시에 동적인 데이타 액세스를 지원할 수 있다. 그러나 기존의 흔성 방송 알고리즘에서 데이타 액세스 변화를 파악하기 위해 사용하는 기법에는 문제가 있다. 즉, 많은 요청을 받은 데이타 아이템을 반복 방송에 추가시키면 액세스 요구가 적어져 이 데이타 아이템이 방송되고 있기 때문에 요청이 적어진 것인지 아니면 수요가 줄어서 요청이 적어진 것인지 모른다는 것이다. 기존 연구에서는 이 문제 때문에 냉각값을 곱해 서서히 제거하는 방법을 사용하거나 일부러 방송에서 누락시켜 수요를 창출하는 방법을 사용한다. 그러나 이 두 방법은 모두 데이타의 특성을 고려하지 않는 인공적인 기법이다. 본 논문에서 이러한 문제를 해결하기 위해 데이타 유형을 분류하여 방송하는 데이타 방송 알고리즘 RTAHB-DT(Real-Time Adaptive Hybrid Broadcasting based on Data Type)를 제안하고, 시뮬레이션을 사용해 제안 알고리즘의 성능을 분석한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.178-180
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• 2007

In this paper, a real-time transmission algorithm based on IEEE 802.15.4 is proposed. The superframe of IEEE 802.15.4 is applied to the transmission method of real-time mixed data (periodic data, sporadic data, and non real-time message). The simulation results show the real-time performance of sporadic data is improved by using the proposed transmission algorithm.

• International Journal of Control, Automation, and Systems
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• 제6권1호
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• pp.119-125
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• 2008

This paper examines the use of a wireless Fieldbus based on IEEE 802.15.4 MAC protocol. The superframe of IEEE 802.15.4 is applied to a transmission scheme of real-time mixed data. The transmission and bandwidth allocation scheme are proposed for real-time communication using a superframe. The proposed wireless Fieldbus protocol is able to transmit three types of data (periodic data, sporadic data, and non real-time messages), and guarantee realtime transmission simultaneously within a limited timeframe.

• 지역사회간호학회지
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• 제4권1호
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• pp.14-24
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• 1993

The Purpose of this study was to explore the condition of periodic medical examination and the health care services of industries in order to offer some basic data on developing industrial nursing care. To achieve this goal a self - administered questionnaire (developed by the academic affairs of community health nursing) was provieded to the nurses in 56 industries from Dec. 10, 1992 to Jan. 20, 1993. The statistical computer package, SPSS, was used to manipulate the data along with T-test and ANOVA. The results were as follows : 1. General characteristics: The greater part of the industries were manufacturing company, and below 300 employees of industry were 55.4%. The shift system was mostly one shift(66.1%) and three shift(23.2%), and 50.0% them organized the Industrial Safety and Health Commitee. Average a number of employees was 631 person. 2. Periodic Medical Examination: Most of the workers were receiving periodic medical examination from the designated hospital (95.71%). From the about 12.89% were gone through a colse medical examination. In colse medical examination 58.41% were decided 'C' and 36.73% were decided 'D'. About 6.23% off those who had any clinical findings were work-time shortening(7.84%), work-transition(8.12%), recoverating at home. The majority of the workers receive the result of the periodic medical examination individually (78.5%). 3. Special medical examination: The rate of those who are receiving special medical examination were 76.82% and about 8.24% were decided 'C' and 1.23% were decided 'D' Those who had any health problems were receiving follow-up checking (9.10%) and medical treatment while working (15.04%). The health managers in the company can consult (85.7%) those who had any suspicious sign and symptoms of occupational disease. 4. Health care services: The average score of health care services were 17.57 point out of 28 point, and the score was lower in health assessment and environmental hygiene than medical diagnosis and health education. There were significant differences in environmental hygine (F=3.72, P=0.017), health care services(F=3.94, P=0.013) according to the size of the size of the industries The other's significancy is not shown by any type of industrial nurse. The level of health care services were higher in the wokers who had better health and showed no singificant differences(T=-0.73, P=0.470).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.362-367
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• 2005

Control network adopted in the national power-plant or manufactory are mostly vendor-dependent products, which have their own special specification, components and individual communication methods. These systems not only raise installation cost, but also bring many difficulties to maintenance and extension. To overcome these problems, this paper introduces a development and application case of a new "PC/Ethernet-based fieldbus" architecture and protocol to be used in mid-level fieldbus. The designed system has a basic idea of "3 Layers fieldbus over Standard-LAN" and implemented on PCs. PC gives user friendly environment. By using an open standard Ethernet in layer 1,2, the system has low cost, wide communication bandwidth and high compatibility. Layer 3 protocol designed for large realtime data communication makes user bypass TCP/IP layer and gives user direct access to the Ethernet. This new protocol eliminates potential collision of Ethernet, and transmits large periodic/non-periodic control data by using long-frame/wide-bandwidth of Ethernet effectively, and offers simple API-Services to the upper layer. Since the system have installed in H-power plant simulator and U-nuclear power plant simulator in Korea, it have been proved to be efficient and stable without any trouble in realtime communication service for full-scope plant simulator that has a lot of control elements.