• 한국기계가공학회지
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• 제20권4호
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• pp.8-15
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• 2021

The effects on system availability, operation, and support costs were analyzed using the M&S system (MPS). The failure frequency items of current armored vehicles were identified and the MTBF of the identified items was improved. The results of this study suggest that when we reduce the frequency of failure, the availability increases, and the operation and support costs decrease. By improving the reliability of the failure frequency items, it becomes possible to upgrade or develop the weapons systems. Through this study, we confirmed that improving reliability will enhance combat readiness and reduce operation and support costs.

• 한국기계가공학회지
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• 제20권2호
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• pp.14-22
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• 2021

A plan for the development of reliability-based ROK amphibious assault vehicles is proposed. By analyzing the development case of the U.S. EFV, considerations for the successful development of the next-generation Korea Forces amphibious assault vehicle are presented. If the vehicle reliability can be improved to the level of the fourth highest priority electric unit for power units, suspensions, decelerators, and body groups, which have the highest priority among fault frequency items, a system level MTBF of 36.4%↑ can be achieved, and the operational availability can be increased by 3.5%↑. The next-generation amphibious assault vehicles must fulfill certain operating and performance requirements, the underlying systems must be built, and sequencing of the hybrid engine and the modular concept should be considered. Along with big-data- and machine-learning-based failure prediction, machine maintenance based on augmented reality/virtual reality and remote maintenance should be used to improve the ability to maintain combat readiness and reduce lifecycle costs.

• 영어어문교육
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• 제18권1호
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• pp.197-216
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• 2012

This study examines spoken interlanguage of Korean learners of English, focusing on the distribution of modal verbs and devices of epistemic modality. (Semi-) spontaneous speech data were collected from four students participating in a self-organized study group for seven months, which produced a corpus of about 55,000 words. The data analysis reveals the following: 1) The frequency of the modal verbs produced by the learners was lower than that of native speakers; 1.99 vs. 2.32 tokens per 100 words. The range of the modal verbs used by the learners was also very limited, with over-reliance on can (43%). 2) The grammatical categories of the devices marking epistemic modality were in the order of adverbs, lexical verbs, and modal verbs, with a high frequency of a few items in each category. 3) Lexical items conveying certainty and modals of obligation were preferred over markers of weaker commitment, resulting in speech characterized by firmer assertions and a more authoritative tone, a potential cause for pragmatic failure. 4) A weak developmental change was observed in the frequency of modal verbs, but not in their functions over the seven month period of data collection. L1 influence, L2 proficiency, mode of communication, and instruction effects are discussed as possible variables involved in the distribution patterns observed.

• 한국안전학회지
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• 제28권5호
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• pp.27-34
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• 2013

Almost accidents in construction sites are occurred by unsafe work conditions and failure making safe environment. As recent construction projects become more complex, various and diversified, So the potential of construction-related accidents is increased as well. Comparing the frequency of construction-related accidents in large-sized construction sites, small-sized construction sites are more vulnerable because of lack of workforce and less effective technology system. Furthermore, the absence of safety committee, poor financial condition leads to lack of safety education, installation of safety facilities, and provision of individual protective equipment, which indicates difficulties handling even basic safety management. Therefore, in order to lower the hazard rate at small-Sized construction sites, it is necessary to proceed with more structural and thorough actions for preventing accidents. In other words, it is necessary to analyze the causes of the accidents at small-sized construction sites, set criteria for safety management, and suggest safety management items according to work classification by evaluating the relative importance of the items.

• 대한치과보철학회지
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• 제43권2호
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• pp.158-175
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• 2005

Statement of problem. Every effort has been continually made to obtain objectivity in measuring the longevity of fixed restorations, such as by establishing unified judgement standard for deciding success and adopting statistical method that analyzes the data of successful and failed cases at the same time. In Korea, however desired level of development has not to be made in this field yet. Purpose. This study, adopting California Dental Association (CDA) quality evaluation system, established objective standard for deciding success, and inferred the longevity of fixed restorations and their failure analysis through adopting Kaplan-Meier survival analysis. Material and method. In order to assess the longevity of flxed restorations serviced in Korea and causes of failure, a total of 1109 individuals (aged 15-74, 716 women and 393 men loaded with 2551 unit fixed restorations, and 1934 abutments) who lived in Kyung-In Province were examined and the findings were as follows : Results. 1. Length of service of fixed restorations serviced in Korea was 6.86$\pm$0.15 yr (mean), 5.5 yr (median), and the rate of success was 65.82% in 5 year survival, and 21.15% in 10 year survival. 2. When there was patient's need for replacing old prosthetics, longevity of fixed restorations was 7.51$\pm$0.27 yr (mean), 7 yr (median), and the rate of success was 61.08% in 5 year survival, and 17.57% in 10 year survival. 3. Longevity of fixed restorations was longest in the over-sixty age group(9.21$\pm$0.66) and that of the teen age group(3.39$\pm$0.28) was shortest (p<0.05). 4. Longevity of fixed restorations of women (7.38$\pm$0.18 years) was longer than that of men (6.00$\pm$0.26) (p<0.05). 5. As for the provider factor (such as unlicensed performers, university hospitals, and private clinic), there was no statistically significant difference in longevity of fixed restorations. 6. Defective margin (34.78%). periodontal disease (12.15%), periapical involvement (11.73%), was the most frequent causes of failure and poor esthetics group showed the longest life above all (p<0.05). Actual frequent causes of failure after removing old prosthetics were defective margin, periapical involvement, periodontal disease and uncemented restoration. In 75.67% of the cases, abutment state after removing old prosthetics was good enough for loading another prosthetics. 7. There was found to have statistically significant influence between longevity of single crown (6.35$\pm$0.20 yr) and that of 3 unit fixed restorations (7.60$\pm$0.30 y) (p<0.05). In each case the most frequent cause of failure was defective margin. 8. The number of cantilever pontic, pontic/abutment ratio, oral hygiene status were found to have no statistically significant influence on longevity of fixed restorations in all groups (p>0.05). 9. Longevity of fixed restorations made of non precious metal was longest (9.60$\pm$0.40 yr) semi precious and precious trailing behind(p<0.05). 10. Group function group (37.04%) and partial group function group (44.62%) were predominant in frequency but showed no correlation between them and among different types of occlusal plane and different types of occlusal surface (p>0.05). 11. Longevity of fixed restorations was longest in the centric interference group(9.35$\pm$0.62) (p<0.05) among different types of occlusal interference. Conclusion. We found that longevity of fixed restorations serviced in Korea is affected by age, gender and type of material, and that most frequent cause of failure is defective margin. In order to assess the accurate longevity of axed restorations, unified research design. overcoming inter-observer difference and establishing the objective research items are needed. Furthermore, it is thought that prospective approach through thorough study and regular follow-ups is needed just from the start of research. Nationwide detailed studies on length of service of fixed restorations manufactured in Korea are hoped to be conducted hereafter.

• 한국정보과학회논문지:시스템및이론
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• 제27권2호
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• pp.188-199
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• 2000

본 논문은 잠금 해제 지연 메모리 모델을 기반으로 하는 분산 공유 메모리 시스템을 위한 효과적이고 안전한 로깅 기법을 제안한다. 제안된 기법에서는 프로세스들 사이의 종속 관계가 추적되어, 실제로 종속 관계가 발생하는 경우에만 안전한 로깅을 수행하는데, 이는 프로세스들 사이에 정보 전달이 일어나는 경우 무조건 로깅을 수행하던 기존의 방법들과 비교 해볼 때, 로깅 횟수가 크게 줄어드는 효과를 낸다. 더욱이. 제안된 기법에서는 각 프로세스가 사용한 데이타를 모두 안전한 저장장소에 로깅 하는 대신, 필요한 데이타들은 그 데이타를 생성한 프로세스의 휘발성 메모리에 로깅하고, 그 데이타의 사용 정보만을 로깅 한다. 프로세스내의 결함 발생 후, 복구 과정에서, 각 프로세스는 로깅 된 사용 정보만을 이용하여 알맞은 버전의 데이타를 효과적으로 찾을 수 있다. 결과적으로 각 프로세스에서 저장되는 로그의 양 또한 줄어든다.

• 컴퓨터교육학회논문지
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• 제8권4호
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• pp.79-86
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• 2005

본 연구에서는 충북 지역 남자 중학생을 대상으로 컴퓨터게임과 학업성취도와의 관계여부를 조사하였다. 조사 대상 학생 중 48%정도가 '컴퓨터게임을 거의 매일 한다'고 응답했고 '컴퓨터게임을 거의 하지 않는다'고 응답한 학생은 전체의 8% 정도였다. 공부를 잘하든 못하든 대부분의 학생들이 컴퓨터게임을 즐기고 있었으며 그 중 상위권 학생들은 한번 게임을 시작하면 1~2시간 이내에서 게임을 마치는 성향을 보였고, 롤플레잉 게임이나 시뮬레이션 게임을 즐기고 액션 게임은 거의 하지 않는 것으로 나타났다. 그리고 성적이 하위권인 학생 중에는 컴퓨터게임을 거의 하지 않는 학생이 상대적으로 많았고, 한 번 게임을 시작하면 3시간 이상 계속하는 게임 중독의 성향을 보이는 학생도 많았다. 또한 성적이 중위권인 학생들은 특이한 차이를 나타내지 않았다. 설문 조사 결과 컴퓨터게임을 자주하는 것과 학업성취도 간에는 관계가 없음을 알 수 있었다. 컴퓨터게임을 자주한다고 해서 성적이 나쁠 것이라는 우려는 하지 않아도 될 것 같다. 다만 공부를 잘하는 학생 중에 컴퓨터게임을 시작해서 3시간 이상 지속하는 학생의 비율은 상당히 적은 것으로 나타났다.

• 한국유통학회지:유통연구
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• 제15권3호
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• pp.71-110
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• 2010

본 연구에서는 항공권 예약 발권 웹사이트의 서비스 품질을 측정 뿐만 아니라 서비스 회복도 측정하고자 하였다. 또한 서비스 품질과 서비스 회복이 고객만족 및 충성의도에 미치는 영향관계를 실증하고자 하였다. 온라인 서비스 품질과 온라인 서비스 회복의 측정을 위해 Parasuraman, Zeithaml, & Malhotra(2005)가 개발한 E-S-QUAL과 E-RecS-QUAL을 사용했으며, 했다. E-S-QUAL은 온라인 서비스 품질을 측정하는 도구로써, 효율성, 시스템 이용가능성, 이행성, 프라이버시의 4개 차원 22개 항목으로 구성된다. E-RecS-QUAL은 온라인 서비스 회복을 측정하는 도구로써, 반응, 보상, 접촉의 3개 차원 11개 항목으로 구성된다. 실증분석을 위한 설문조사는 항공사나 여행사의 웹사이트를 통해 국내 외 항공권을 구입해 본 경험이 있는 소비자를 대상으로 실시하였는데, 총 400부가 회수되었고, 이 중 342부를 최종분석에 사용하였다. 실증분석을 위해 AMOS 7.0과 SPSS 15.0을 사용하였다. 먼저, SPSS 15.0을 사용하여, 요인점수를 이용한 회귀분석으로 가설검증을 한 결과, <가설 I-1, 2, 3, 4, II-1, 2, 3, III-1, IV-1>이 전부 채택되었다. 온라인 서비스 품질과 온라인 서비스 회복의 각 차원은 모두 전반적인 서비스 품질에 유의한 영향을 보였고, 전반적인 서비스 품질은 고객만족에 유의한 영향을 미쳤다. 마지막으로 고객만족 역시 충성의도에 유의한 영향을 미치는 것으로 확인되었다. 한편 AMOS 7.0을 사용하여 모형 분석을 하였는데, 모형의 적합도는 가설검증을 하기에 합당한 수치가 나왔다. 이를 토대로 가설검증을 한 결과, <가설 I-1, 3, II-1, 3, III-1, IV-1>은 채택되었고, <가설 I-2, 4, II-2>는 기각되었다. 이 결과는 Parasuraman et al.(2005)이 주장한 것처럼 E-S-QUAL을 나타내는 데는 요인점수를 이용한 회귀분석이 더 적합하다는 것을 보여주는 것이라고 판단된다. 이를 토대로 본 연구의 시사점을 정리하였다.