• 한국신뢰성학회지:신뢰성응용연구
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• 제11권4호
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• pp.399-407
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• 2011

Reliability evaluation of One-Shot system which flies at speed of Mach must be evaluated as the result of many firing tests. But many firing tests are impossible because of budget deficit. Consequently the reliability prediction which substitutes firing tests is used. The accuracy of reliability prediction is decided according to a quantity of accumulated test data. If the test data is insufficient, the direction of prediction can not be set. So we propose the reliability prediction method which applies MIL-HDBK-217 Plus. MIL-HDBK-217 Plus is described about reliability prediction method without sufficient test data. So we apply MIL-HDBK-217 Plus to the rocket motor system, and we accomplish a modeling and a reliability prediction about the system.

• 대한치과보철학회지
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• 제35권4호
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• pp.706-718
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• 1997

Ceramometal crowns are common restorations in fixed prosthodontics because of their casting accuracy, the high strength properties of the metal, and the cosmetic appearance of porcelain. However, deterioration of the initial fit of the metal coping has been observed after the porcelain firing cycle. The distortion due to repeated firing makes it difficult to fit crown margin and elicits microleakage. The major causes of distortion are the residual stress that accumulate during wax-up, casting, cold work and the induced stress caused by the mismatch of porcelain-metal thermal contraction. This study examined the marginal fit changes of metal copings in relation to repeated firing and the effects of heat treatment that reduce the distortion resulted from residual stress. The marginal changes of the copings that were treated with conventional method and those treated with heat before repeated firing, were evaluated. The metal die which represented preparations of a maxillary central incisor was fabricated, and 45 wax patterns were cast with nonprecious metal alloys. The heat treatment of each group was performed as follows. Group 1(control) : Casting - Devesting - Cold work - Firing Group 2 : Casting - Heat treatment - Devesting - Cold work - Firing Group 3 : Casting - Devesting - Cold work - Reinvesting - Heat treatment - Devesting - Firing The copings were fired 3 times. After each firing, the marginal fit changes were measured with inverted metallurgical microscope at the 4 reference points located at labial, lingual, and both proximal surface. Measurements were compared, and statistically analyzed. The results were as follows ; 1. In all groups, the highest value of marginal fit changes of the copings studied were found after the first firing cycle. 2. When the distortion of each experimental group at the first firing cycle were compared, group 1 exhibited the greatest changes($20-27{\mu}m$), followed by group 2($9-13{\mu}m$), and group 3($8-10{\mu}m$). 3. The copings treated with heat before devesting(group 2) revealed significantly smaller marginal fit changes than the copings treated with conventional method(group 1). (p<0.01) 4. The copings treated with heat after reinvesting(group 3) revealed significantly smaller marginal fit changes than the copings treated with conventional method(group 1). (p<0.01) 5. No siginificant differences in marginal fit changes were found between the copings treated with heat before devesting(group 2) and the copings treated with heat after reinvesting(group 3). (p>0.01)

• 지구물리와물리탐사
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• 제6권2호
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• pp.71-76
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• 2003

정확한 초동 발췌는 고해상 속도 토모그램 도출에 중요한 요소이다. 주시 발췌의 정확도에 영향을 주는 2가지 요인은 지질학적 요인과 기계적인 요인이 있다. 중요한 기계적인 요인은 발파시간 제어이다. 임펄시브형 시추공 탄성파 송신원에 의한 기록에서 다음과 같은 문제가 확인되었다. 즉, 불규칙한 발파시간 제어 문제와 기록에 나타난 발파시간의 불확실성이다. 이러한 발파시간 문제는 발췌된 초동에 정확도를 저하시키게 되며, 따라서 속도 토모그램을 왜곡시키게 된다. 본 연구에서는 수평방향의 속도와 NMO 속도를 반복적으로 비교함으포써 최적의 발파시간을 산출하는 방법을 제시하였다.

• 대한기계학회논문집A
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• 제39권6호
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• pp.611-615
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• 2015

비행기 방어용 대공포는 저고도 방어체계로 사용되고 있으며, 방어능력 극대화를 위해 대부분 고발사율 대공포를 두개 이상 탑재하여 교전 시 명중률을 높이고 있다. 고 발사율 대공포의 경우, 포열진동 및 탄의 불균형 분산은 정확한 조준사격 및 명중률에 아주 결정적인 영향을 미치게 된다. 따라서 사격 진동 및 충격량을 감소하는 구조는 대공포 체계에서는 주요 설계 대상이다. 본 연구에서는 차량의 현가장치 특성에 따라 고발사율 대공포 체계에서 발사시스템의 진동충격으로부터 차단하는 능력을 향상시키고, Recurdyn 과 Adams 를 이용한 동적 거동해석과 실 사격 시험결과를 비교하여 명중률에 영향을 미치는 현가 형태, 위치 및 수량에 따른 체계 자세 흔들림을 예측하였다. 본 연구를 통하여 대공포에 적합한 현가장치와 포 스프링 등과 같은 구성품을 선정할 수 있는 기초연구를 수행하였다.

• 한국군사과학기술학회지
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• 제6권4호
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• pp.22-28
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• 2003

In the conventional weapon system, such as gun and small arms, it Is a general trend that for maximization of its performance and enhancement of its effectiveness, the firing control system(FCS) is developed and applied with the guns and small arms in the world. The FCS of the small arms for infantry man is composed of a few of sensors for acquisition of input data of FCS, such as range measurement, position sensing of weapon, temperature, etc., computer, displayer and power pack, and also the air burst munition is developed in parallel for the maximization of FCS's effectiveness. Since the flight time setting fuze for the air burst munition is adapted for next me, the measuring device of the muzzle velocity is needed to overcome the variation of muzzle velocity due to producing procedures and the differences of the using temperatures and so maintain the burst position accuracy This paper contained the technical information on the development of the measuring device of muzzle velocity, which designed in compact & light weight configuration with reliability and accuracy.

• 한국군사과학기술학회지
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• 제12권2호
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• pp.133-138
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• 2009

A mortar system is able to be fired more rapidly and concentratedly than other field gun systems. A mortar system can be easily manufactured because of its simple structure. It has also been supporting for the fire power of infantry because it can be carried conveniently. But a mortar system has demerits that are the limited firing range, poor accuracy and uncomfortable operability. Korean army plan to be operated rapidly and enlarge battle field in the near future. So weapon systems of Korean army must have longer firing range, automatic laying function and precision firing capability. This study suggests efficient developing concept of 120mm self-propelled mortar system through surveying the technical readiness level of current R&D and manufacturing ability.

• 한국추진공학회지
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• 제11권2호
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• pp.62-70
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• 2007

지향성능은 발사차량의 정확성에 있어서 중요한 요소이다. 본 연구는 외란 가속도를 이용하여 지향구조물의 진동을 감지하는 방안과 실험 결과에 대하여 기술하였다. 주행 중 발생하는 진동 경향을 분석하기 위하여 가속도 자료를 이동평균과 힐버트 변환을 이용하여 신호 처리하였다. 다양한 외란에 대하여 가속도의 모드 계수를 얻었으며, 차량속도, 노면조건, 지향구조물의 특성을 차량 동특성의 진동을 변화시키는 요소로 간주하였다. 마지막으로 다양한 주행 조건의 진동 신호를 분류하기 위한 패턴인식에 역전파 신경망 이론을 이용하였다. 각 조건에 대하여 실험 결과를 비교 분석하였다.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2011년도 춘계학술발표대회 논문집
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• pp.305-309
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• 2011

Reliability evaluation of One-Shot systems which fly at speed of Mach must evaluate as the result which leads a many firing test. But many firing test the fact that is impossible is actuality with problem of budget. Method of prediction leads consequently with alternative and will be able to present the alternative which evaluates. Prediction of One-Shot systems that how many did accumulate a many experience data according to the accuracy is decided, there is a possibility of seeing. One like shot our country and the method which is indirect leads from the environment where the test data is insufficient and only will not be able to set the direction of prediction, the present paper about such method describes 217 Plus where is a reliability prediction standard which is new the thing in standard.

• 한국군사과학기술학회지
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• 제13권4호
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• pp.551-560
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• 2010

In this paper, we suggest a localization method of factors affecting the accuracy of Air-to-Ground weapon delivery. The proposed method, called FBEL(Factor-Based Error Localization), is based on the fault localization technique widely utilized in the realm of software engineering field. FBEL localizes the major factors affecting the performance of weapon delivery. To analyze the effectiveness and the applicability of FBEL, we applied FBEL to real firing data and got the major factors caused the errors. We expect that the method could contribute to improve the quality of weapon delivery system. We also expect that it may aid improvement of pilot capability greatly, if it is applied to pilot firing training.

• 한국시뮬레이션학회논문지
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• 제26권3호
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• pp.55-63
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• 2017

곡사포의 사격오차는 탄착의 분산도와 탄착중심오차(MPI)를 포괄하는 용어로, 본 연구에서는 사격시험을 수행하지 않고 정량적 분석을 통해 사격오차를 예측하는 기법에 대해 논하고자 한다. 기존에도 곡사포의 사격오차를 예측하기 위한 분석기법은 있었지만, 오차에 관여하는 영향요소들에 대한 정보가 부족하여 활용이 제한되었다. 본 연구에서는 이런 문제를 해결하기 위해 누적된 시험이 수행된 기존 무기체계 시험결과를 활용하여, 오차의 원인이 되는 각 요소 값들을 역으로 산출하는 방식을 제안한다. 이 과정에서 항공공학 분야에서 흔히 사용되는 최적화 알고리즘을 이용한 입력계수 추출 방식을 도입하였다. 최적화 알고리즘으로는 CMA-ES라는 진화적 기법을 소개하며, 적용 결과에 대하여 해설하였다. 이런 과정을 통해 얻은 사격오차요인 값은 향후 신규 무기체계 개발에 있어 성능요구사항 산출에 사용될 수 있으며, 야전에서의 곡사포 정확도 향상에도 기여할 것으로 보인다.