• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.1914-1925
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• 2014

Inter-symbol interference (ISI) problem is inevitable when the guard interval (GI) is shorter than the delay spread (DS) for an orthogonal frequency division multiplexing (OFDM) system. Iterative techniques have been proposed to overcome such a problem. However, most of existing algorithms are not efficient for an OFDM system with a small GI working under the channel with a large DS. Especially in the case of the DS spans a longer time than the half of the OFDM symbol duration. On the other hand, conventional algorithms, which can reduce the effects of the severe ISI, often employ several impractical assumptions to support the conclusions. In this paper, we present a robust decision feedback equalizer (DFE) for the OFDM system to overcome the severe ISI problem. The proposed DFE removes the ISI in a same manner as the residual inter-symbol interference cancellation (RISIC) algorithm. However, the inter-carrier interference (ICI) is reduced via cyclicity removal instead of the cyclicity restoration used in the conventional algorithms. The link-level simulation (LLS) results indicate that our proposed DFE scheme can dramatically improve the BER performance when the DS spans longer than the half of ODFM symbol duration.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.341-347
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• 2005

To perform a cryogenic development test for Tribo-elements in a turbopump, a cryogenic bearing and seal test facility (BSTF) is designed and currently under construction in KARI. The working fluid is liquid nitrogen operating at a temperature $-197^{\circ}C$. The maximum operating pressure and volume flow rate of BSTF are 100 bar and 10 liters per second, respectively. The development tests of floating ring seals, inter-propellant seals (IPS) and cryogenic ball bearings in a turbopump will be performed using the BSTF. This paper briefly described design requirements and procedures of BSTF.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.435-436
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• 2006

When working with multi-view images, imbalances between multi-view images occur a serious problem in multi-view video coding because they decrease the performance of disparity estimation. To overcome this problem, we propose inter-view balanced disparity estimation for multi-view video coding. In general, the imbalance problem can be solved by a preprocessing step that transforms reference images linearly. However, there are some problems in pre-processing such as the transformation of the original images. In order to obtain a balancing effect among the views, we perform block-based disparity estimation, which includes several balancing parameters.

• Journal of Korean Public Health Nursing
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• v.4 no.2
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• pp.59-77
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• 1990

The purpose of this study was to provide the basic data for the effective health management of the industrial workers, by classifying factors influencing their perceived symptoms to examine their health status and identifying the inter' relationship of their perceived symptom with their working department. the environment of working area and their general characteristics. The study was undertaken from October 1 to November 30. 1989. The subjects were 999 workers who had worked in Industrial Corps located in Chungbuk Province. The results of this study were as follows: I . Worker's perceived symptoms were classified according to the following eight factors; 1) musculo - skeletal symptoms of shoulder, neck, back and arm 2) optical symptoms 3) symptoms in head(such as headache and dull) 4) musculo - skeletal symptoms of leg and lower back 5) gastro - intestinal symptoms 6) mental symptoms. 7) neural symptoms 8) lung and heart symptoms II . The degrees of workers' perception of perceived symptoms; Mean score of perceived symptoms:7.0 The rank of degrees of perceived symptoms: The highest:musculo - skeletal symptoms of shoulder, neck, back, and arm The second:optical symptoms The third:musculo - skeletal symptoms of leg and lower back The fourth:mental symptoms the fifth:gastro-intestinal symptoms m . Analysis of the inter-relationship of perceived symptoms with working department, environment of working area and general characteristics; 1) sexuality The difference of degrees of perceived symptoms was significant;femanle was higher than male(P<0.000). 2) level of education The difference of degrees of perceived symptoms according to the level of education was significant; The higher the level of education, the higher the degree. 3) working department The working department played a significant part in the degrees of perceived symptoms of workers; Workers of assembling department:musculo-skeletal symptoms both of shoulder. neck, back and arm and of leg and lower back(P<0.000). Workers of inspection department:optical symptoms(P<0.05). Office workers:mental symptoms(P<0.05). 4) kinds of job The difference of the degrees of perceived symptoms according to kinds of job was significant; Workers dealing with chemical materials and workers dealing with job with high tension:gastro-intestinal symptoms and symptoms in head. Workers dealing with weighty things or working a long time with the same posture:musculo-skeletal symptoms both of shoulder, neck, back and arm and of lower back(P<0.000). 5) working posture The difference of the degrees of perceived symptoms related with working posture was significant; Sitting:optical symptoms(P<0.0000) and symptoms in head(P<0.005) Standing:musculo-skeletal symptoms of leg and lower back(P<0.0000). 6) satisfaction with their own duty The more dissatisfien they were. the higher became the degrees of their perceived symptoms(P<0.0001). 7) satisfaction with their working condition The more dissatisfied with their working condition they were, the higher became the degrees of their perceived symptoms(P<0.001). 8) environment of working area The environment of working area played a significant part in the degrees of perceived symptoms of workers; Workers exposed to most of the factors of the environment of working area were higher than those not exposed in the degrees of musculoskeletal symptoms. Workers in the noisy environment:optican symptoms(P<0.000), symptoms in head(P<0.005). Workers in the damp environment:optical symptoms(P<0.005) and lung and heart symptoms(P <0.01). Workers with illumination problem:optical symptoms(P<0.000), mental symptoms(P<0.005) and neural symptoms(P<0.01). Workers with ventilation problem:optical symptoms and lung and heart symptoms(P<0.001)

• Journal of Korean Academy of Nursing
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• v.15 no.3
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• pp.39-49
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• 1985

The study was carried out to measure the degree of work stress among clinical nurses, and to identify factors influencing the work stress. Data was collected from 215 staff nurses working in the Seoul National University Hospital from the end of February to first of march, 1984. The results and suggestion of study were: 1. Nurses perception of work stress. 1) Mean score of total work stress of nurses was 4.467, when maximum score was 6. High degree of work stress is evident among nurses. 2) The highest rank of stress factor was inter-personal relationship with physicians, night duty, heavy work load, inadequate working condition and payment were other stress factors. 2. Relationships between situational variables and degree of stress. There was significant correlation-ship between nurse's total work stress score and educational levels (r=0.153, p=0.032).

• Proceedings of the ESK Conference
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• 1996.04a
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• pp.91-97
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• 1996

This study is to analyze trends of back injuries reported for medical expense compensation in a territorial jurisdiction of Pohang regional office of Ministry of Labor. Back unjuries claimed in the Plhang region accounted for approximately 15% of all industrial accident and 0.96 billion won were spent to compensate for medical expenses in 1994. A majority of back injuries occurred in manufacturing, construction, and transportation, and, 98% of all back injuries during 1992-1994 were strain/sprain, herniated inter-vertebral dise(HIVD), and fracture. To achieve and effective back injury prevention, supplenentary reporting form should be provided to include the information about job description (e.g., weight of an object, task duration and working posture), employee's medical and work history, and working conditions.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.81-84
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• 2000

This paper has been studied a interworking signalling protocol between two hybrid networks by analyzing Satellite B-ISDN architecture, DSS2 Layer 3 Signalling protocol B-ISUP protocol, S-BISUP protocol stack and so on. Also in the paper, messages and primitives have been defined for B-ISDN's Connection Type, Ownership and each protocol in order to connect point-to-multipoint. And then this paper has designed basic call procedures for OBP Satellite B-ISDN NNI inter-working protocol, verified and implemented them.

• 한국경영정보학회:학술대회논문집
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• 2007.11a
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• pp.377-382
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• 2007

To transform the enterprise system into the 'Real Time Enterprise' with respect to IT, I suggest the conceptual application model which is composed of pieces(components) extracted from different packaged applications working in a heterogeneous environment based on the 'business activity' in other words, business services provided by internal (inter-enterprise) and external (extended enterprise) application to support a business activity within in an enterprise and the design mechanism focusing service tier which acts as intermediate tier within application architecture.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.916-920
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• 1987

This paper describes the maintenance function and administration function in the IWS (InterWorking System between PSTN and PSDN) which Interconnects the PSTN and PSDN. The former function is for the stable operation of the IWS system, and the latter function is for the management of the subscriber, billing and statistics informations.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.911-915
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• 1987

In this thesis, the architecture and design of IWS(Inter Working System) which interconnects two different networks (PSDN: Packet Switched Data Network, PSTN:Public Switched Telephone Network) are described. IWS provides interconnection services for the compatibility of communication between two networks. IWS consists of network interface protocols, protocol conversion facilities and management facilities.