• 한국음향학회지
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• 제13권6호
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• pp.66-74
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• 1994

잔향음이 우세한 환경하에서 소나 시스템의 성능을 평가할 때 대부분의 음향 모델인 음압 준위(power level) 모델에 비해 수중 잔향음 신호 모의 모델은 매우 유용하게 이용된다. 본 논문에서는 소나 시험에 필요한 잔향음 신호(reverberation time series)를 모의하였다. 우선 주파수 영역에서 밴드의 폭이 변하고 가우시안 분포(Gaussian distribution)를 갖는 표준화된 스펙트럼(normalized spectrum)을 수신 시간 간격에 따라 구하였다. 두번째로, 기존의 음향 모델의 결과인 시간에 따른 잔향음 준위를 각각의 표준화된 스펙트럼의 준위와 합성하였다. 마지막으로 음원 신호의 스펙트럼과 잔향음 스펙트럼을 곱(product)하고 이 결과를 역푸리에 변환(inverse Fourier transform)을 이용하여 신호를 모의하였다.

• 한국안전학회지
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• 제23권1호
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• pp.46-50
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• 2008

The purpose of the present study was to investigate the mariner's information characteristics in ship-ta-ship collision situation using the full mission ship-handling simulator. Risk levels of ship-to-ship collision were manipulated by whether the target ship complies with the naval regulations and by movement patterns of target ship. Dependent variables reflecting mariner's information characteristics in ship-ta-ship collision situation were measured in terms of radar detection reaction time, free recall performance of past navigation situation, and subjective ratings for the task difficulty. The results showed that, in general, the mariners appeared to be deteriorated in their radar detection reaction time and free recall performance as the risk of ship-ta-ship collision increased. Also, the mariners tended to rate required tasks more difficult in the high risk ship-ta-ship collision situation.

• 전기학회논문지
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• 제62권8호
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• pp.1192-1197
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• 2013

In this paper Ubiquitous Medical Electronic Device Export was defined, and it's job analysis. The authors have been defined the job and classified duties and tasks of Ubiquitous Medical Electronic Device Export. To fine what is the most efficient task for Ubiquitous Medical Electronic Device Export, we have been investigated the levels of importance, difficulty, frequency and entry in each task. A DACUM committee is composed of total 12 members, which are one facilitator, 10 panel members, one coordinator & recorder to analyze the job of Ubiquitous Medical Electronic Device Export. Following is the result of this study. First, The process began with the identification of a job title and definition of Ubiquitous Medical Electronic Device Export. Second, a job model of Ubiquitous Medical Electronic Device Export is constructed based on the results of DACUM job analysis. 5 duties and 33 tasks are analyzed. Third, occupational specification was drawn up in consultation with SME council. Fourth, duty specification was drawn up in consultation. 33 tasks that are essential in entry level of occupation are identified. Fifth, task specification was drawn up in consultation. Detail task component which include skill, materials, knowledge, equipment, achievement level and tool was specified in task specification.

• 경영과학
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• 제12권2호
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• pp.129-146
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• 1995

As society's relience on computerized information systems to support a wide range of activities proliferates, the long recognized importance for adequate data quality becomes imperative. Furthermore, current trends in information systems such as dispersal of the data resource together with its management have increased the difficulty of maintaining suitable levels of data integrity. Especially, the importance of adequate accounting (transaction) data quality has been long recognized and many procedures (extensive and often elaborate checks and controls) to prevent errors in accounting systems have been introduced and developed. Nevertheless, over time, even in the best maintained systems, deficiencies in stored data will develop. In order to maintain the accuracy and reliability of accounting data at certain level, periodic internal checks and error corrections (internal audits) are required as a part of internal control system. In this paper we develop a general data quality degradation (error accumulation ) and cost model for an account in which we have both error occurrences and error amounts and provide a closed form of optimal audit timing in terms of the number of transactions that should occur before an internal audit should be initiated. This paper also considers the cost- effectiveness of various audit types and different error prevention efforts and suggests how to select the most economical audit type and error prevention method.

• 정보관리학회지
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• 제22권3호
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• pp.213-232
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• 2005

본 고의 목적은 초등학생용 독서자료의 텍스트수준에 영향을 미치는 요인들을 규명하여 텍스트수준 측정 공식을 구성함으로써 텍스트의 수준 평가를 자동화하는 데에 있다. 컴퓨터로 계량화할 수 있는 언어적 요인들을 대상으로 표본집단에 부여된 텍스트수준 점수와의 상관관계를 검토한 결과 글자수, 어절수, 이형어절수, 문장수, 단락수 요인이 텍스트수준을 결정하는 요인으로 드러났다. 단순회귀분석을 통해 도출된 회귀방정식들 중에서 이형어절수 모형이 최적의 공식으로 드러났으나, 중회귀분석을 한 결과 이형어절수요인과 새 어절출현비율요인을 결합한 모형은 설명력이 더욱 향상된 공식으로 밝혀졌다. 공식에 따라 측정된 텍스트수준 점수는 학년 내에서 매우 세분된 단계까지 나타내고 있으므로 각 학생별로 그들의 독서능력에 적합한 자료를 추천할 수 있다.

• 해양환경안전학회지
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• 제2권S1호
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• pp.63-73
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• 1996

The assesment of the safety of ship's transit in a curved narrow channl consists of the maneuvering safety determined by the chance of running aground, the maneuvering difficulty determined by shop's workload, and shiphandler's subjective evaluation. In this study to examine the correlation between shiphandler's subjectice evaluation and the maneuvering risk, the real-time and full-mission shiphandling simulator in the Korean Marine Training & Research Institutes(KMTRI) was utilized. In the conning bridge of the shiphandling simulator, 50 experienced masters conducted masters conducted the modeled vessel of 60,000 deadweight tonnage along the designed channel under 3 different envrinmental conditions. The findings were as follows: (1) The frequencies of stress levels, work difficulties, vessel controllability and overall workload of shiphandlers are similar irrespective of environmental conditions and they are able to be represented as shiphandler's subjective evaluation. (2) It is possible to assess and analyze theoretically the correlation between the shiphandler's subjective ecaluation and maneuvering risk each environmental cindition by quantifying the data obtioned from the tests. The results are as follows: ① As the degree of maneuvering risk increases, the shiphandler's subjective evaluation increases sharply near the curvature area of the desgined channel. ② In the area of the curvature of the designed channel, maneuvering risk increases sharply with the danger of running aground under the environmental condition of current and wind comung from the stem.

• Architectural research
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• 제15권1호
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• pp.9-15
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• 2013

Effects of physical attributes of workstation enclosures on the performance of office workers with different difficult levels of office tasks and moods are presented. Performance scores in complex tasks were expected to increase with greater workstation enclosures while those in simple tasks would be the same. Mood ratings were expected to be higher in lower workstation enclosures. Performance of 102 college students on ambient office sounds (45 dBA) with office tasks were measured for 100 minutes under three different workplace enclosures: (1) four foot partitions on two sides; (2) six foot partitions on three sides; and (3) a fully enclosed workstation with eight foot partitions. The tasks were to memorize a paragraph with 130 words (complex task) and to search phone numbers (simple task). The complex task performance in the fully enclosed workstation was increased compared to that in the workstation with four foot partitions (p < 0.001) and to that in the workstation with six foot partitions (p < 0.05). However, occupants in the fully enclosed workstation with office sounds without speech generally gave higher mood ratings. It indicates that closed individual offices may offer important contributions to collaborative work as well as individual productivity. These findings would help design community revise open plan design to increase collaboration among office workers.

• 한국정밀공학회지
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• 제19권12호
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• pp.38-44
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• 2002

A walking training robot is proposed to provide stable and comfortable walking supports by reducing body weight load partially and a force control of an arm of walking training robot using sliding mode controller is also proposed. The current gait training apparatus in hospital are ineffective for the difficulty in keeping constant unloading level and for the constraint of patients' free walking. The proposed walking training robot effectively unloads body weight during walking. The walking training robot consists of an unloading manipulator and a mobile platform. The manipulator driven by an electro-mechanical linear mechanism unloads body weight in various levels. The mobile platform is wheel type, which allows patients to walt freely. The developed unloading system has advantages such as low noise level, lightweight, low manufacturing cost and low power consumption. A system model fur the manipulator is established using Lagrange's equation. To unload the weight of the patients, sliding mode control with p-control is adopted. Both control responses with a weight and human walking control responses are analyzed through experimental implementation to demonstrate performance characteristics of the proposed force controller.

• 한국전자통신학회논문지
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• 제10권3호
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• pp.349-356
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• 2015

광학적 잡음과 전기적 잡음을 복합적으로 제거할 수 있는 하이브리드 필터를 채용하고 펄스형태의 아크 광 신호를 적분하여 수신되는 아크에너지의 크기로 감지할 수 있는 원격감시 기능을 갖는 고감도 부분방전 센서를 구현하였다. 하이브리드 필터는 부분방전 센서가 설치되는 배전반 내 환경에서 내부 형광등과 백열등 조명에 대하여 영향을 받지 않음을 보여주었다. 종래에는 아크광의 불규칙한 파형특성으로 인하여 첨두치가 감지되어 아크광의 크기에 비례한 선택적 감지가 어려웠으나, 센서에 적용된 적분연산 기능은 각기 다른 아크광의 에너지 레벨에 대하여도 선택적으로 감지가 가능함을 실험적으로 보여주었다. 센서는 2m 이격된 원격지에서 100A 저압 MCCB의 정상 개폐 시 발생하는 섬광에 해당하는 광 에너지에 대해서도 감지가 가능함을 보여주어 원격감시 기능을 갖는 고감도 부분방전센서에 적용 가능함을 보여주었다.

• 한국초등과학교육학회지:초등과학교육
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• 제25권1호
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• pp.89-95
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• 2006

The purpose of this study was to examine elementary teachers' perception on birds and problems on teaching it. For this study, the science textbooks from 3rd grade to 6th grade according to the 7th national curriculum were analyzed. Results revealed that, firstly, there were 34 bird species recorded and these were described 55 times in the surveyed textbooks. Secondly, the survey showed that $20\%$ of the teachers were interested in birds despite the fact that $98\%$ of them had no special knowledge about birds nor had studied them in college. Additionally, it was revealed that $41\%$ of the teachers felt lacking in specialist knowledge about birds and this lead to difficulties in teaching on this subject. Thirdly, academic backgrounds had an affect teachers' perceptions on teaching this area. The teachers' levels of interest in birds and the teachers' ratio of teaching on this topic tended to increase as their academic careers developed, and the proportion of male teachers in this category were higher than female teachers. To overcome difficulty in teaching on this area, it is suggested that a reconstitution of subject materials, as well as a revision of the teachers' guidebooks be undertaken.