• 해양환경안전학회지
• /
• 제27권2호
• /
• pp.238-246
• /
• 2021

어선과 같은 소형선박의 충돌사고는 큰 인명피해를 초래한다. 본 연구 이전에 선행된 연구에서는 충돌위험을 판단하고 경보를 발생시키는 소형선박 충돌예방 알고리즘을 개발하였다. 하지만 충돌경보와 같이 안전을 위해 제공되는 서비스는 위험을 예방할 뿐 아니라 이용자의 만족도 또한 어느 정도 수반되어야 효과적으로 기능할 수 있다. 본 연구에서는 소형선박 충돌예방 알고리즘의 실용성 향상을 위해 알고리즘을 개선하고, 알고리즘을 실제로 적용하여 개선결과 및 효과를 확인하고자 하였다. 충돌경보 서비스를 사용한 소형선박 운항자들을 대상으로 설문조사를 수행한 결과, 충돌경보의 정확도 향상과 경보 횟수 및 음량에 대한 사용자들의 요구사항이 확인되었다. 이에 따라 본 연구에서는 사용자 만족도 향상을 위해 알고리즘을 개선하였으며 실제 해상환경에서 개선된 알고리즘을 적용한 실선실험을 수행하였다. 그 결과 개선 전보다 경보 발생 빈도가 감소하였지만, 위험한 상황에서는 경보가 비교적 꾸준히 발생하였으며, 충돌경보의 정확성과 실용성이 향상된 것으로 분석되었다. 추후에는 개선된 알고리즘의 적정성에 대한 근거자료를 마련하여 알고리즘의 실용성과 신뢰성을 확보한다면 소형선박 충돌사고 예방에 효과적으로 기여할 수 있을 것이다.

• 사상체질의학회지
• /
• 제7권2호
• /
• pp.59-88
• /
• 1995

Three groups have participated in this study. 1) The first group consists of 57 patients were who had been treated in the Oriental Medical Hospital at Kyung Hee Medical Center. 2) The second group consists of 37 outpatients who had been treated in the Oriental Medical Hospital at Kyung Hee Medical Center. 3) The third group consists of 76 students of the Oriental Medical School at Kyung Hee University. The following conclusions were made in comparison with EAV measurement values, SaSang Constitution Classfication and CVA. 1. The following conclusions were made in comparison with EAV measurement values and Type(SaSang Constitution Classfication). 1) The analsis of the Correlation in Normal group with EAV measurement values and Type(SaSang Constitution Classfication). 2) The analysis of the correlation in patient group with EAV measurement values showed significant differences in Right meridians(Nerval degeneration vessel, Circulation, Allergy) and in Left meridian(Liver). 3) The analysis of the correlation in Total(Normal+patient)group with EAV measurement values showed significant differences in Right meridians(Large intestine, Nerval degeneration vessel, Circulation, Allergy, Pancreas) and in Left meridians(Lymph vessel, Nerval degeneration vessel, Spleen, liver). 4) The above results showed common-significant differences in Right Allery meridian and in Left Liver meridian. 2. The analysis of the correlation in EAV measurement values and Group (Cerebrovascular accident) showed significant differences in Right meridians(Lymph vessel, Lung, Nerval degeneration vessel, Allergy, Paren & Epith. degeneration vessel, Triple warmer, Heart, Pancreas, Stomach, Fibroid degeneration vessel, Skin, Fatty degeneration vessel, Heart, Stomach, Fibroid degeneration vessel, Skin, Fatty degeneration vessel, Bile duct, Kidney). 3. The analysis of the correlation in EAV measurement values and Para(GROUPS according to PARALYSIS)showed significant differences in Left Stomatch meridian. The analysis of the correlation in EAV measurement values and Para(GROUPS according to PARALYSIS) about the differance of right measurement values and left measurement values showed significant differences in Nerval degeneration vessel, Stomatch, Gall bladder & Bile duct, Kidney and Urinary Bladder meridians. 4. The analysis of the correlation in EAV measurement values and Compl(GROUPS according to COMPLICATION with CVA)showed significant differences in Right meridians(Lymph vessel, Articular degeneration vessel, Fatty degeneration vessel) and in Left meridians(Lung, Stomatch, Fatty degeneration vessel). 5. The analysis of the correlation in Type and MORPHOROGICAL DIAGRAMING (HTOUPS according to MORPHOROGY) showed significant differences in Cranium region, Chest region, Stomatch region and Umbilicum region. 6. The analysis of the correlation in BAZ measurement values and Group(Cerebral Vascular Attack)showed significant differences, the analysis on the correlation of BAZ measurement values and Type(SaSang Constitution Classfication) didn't show any significant differences. 7. In comparison with Actual measurement vales and Voll's measurement values, BAZ measurement values agree with Voll's measurement values but CMP measurement values lower than the Voll's measurement values. Later We have to research further about classifications of race, age, sex etc. The EAV measurement values have Group(Cerebrovascular accident) more correlative than Type(SaSang Constitution Classfication). The EAV may well be that it will be used as an accessory method in SaSang Constitution Classfication and as a diagnostic method in medicine too.

• 한국기계가공학회지
• /
• 제18권8호
• /
• pp.67-73
• /
• 2019

An ultra-high pressure treatment device is a device used for increasing the shelf life of food by sterilizing it by applying hydrostatic pressure to solid or liquid food. The ultrahigh pressure treatment system developed in this study is a pressure vessel with a processing capacity of 100 L and a maximum pressure of 700 MPa. Pressure vessels for ultrahigh-pressure processing equipment are manufactured using wire-winding techniques. The design formula for making ultra-high pressure vessels with wire windings is given in ASME Section VIII - Division 3. In this study, the ratio of the cylinder to the winding area that can be applied in a wire-winding application was analyzed using a finite element analysis. Furthermore, the relationship between the variation of the residual stress in the vessel and the ratio of the winding area due to the variation of the winding tension was analyzed, and a design guide applicable to the actual product design was developed. Finally, the design equation was modified by presenting the coefficients to correct the difference between the finite element analysis and the design equation.

• 한국압력기기공학회 논문집
• /
• 제15권1호
• /
• pp.71-76
• /
• 2019

Actual stress distributions in the nozzle of a pressure vessel may not be in plane strain condition, implying that the crack-tip constraint condition may be relaxed in the nozzle. In this paper, a methodology for evaluating the fracture toughness of the ASME Code is presented considering the relaxation of the constraint effect in the nozzle of the reactor pressure vessel. The crack-tip constraint effect is quantified by the T-stress. The equation, which represent the relation between the fracture toughness in the lower constraint condition and the plane strain fracture toughness, is derived using the T-stress. This equation is similar to the method for evaluating the fracture toughness of the Master Curve for low constraint conditions. As a result of evaluating the fracture toughness considering the constraint effect in the reactor inlet, outlet and direct injection nozzles using the proposed equation, it was confirmed that the fracture toughness in the nozzles is higher than the plane strain fracture toughness. Applying the proposed evaluation methodology, it is possible to reflect the relaxation of the constraint effect in the nozzles of the reactor pressure vessel, therefore, the safe operation area on the pressure-temperature limit curve can be prevented from being excessively limited.

• 한국항해항만학회지
• /
• 제43권1호
• /
• pp.16-22
• /
• 2019

본 연구에서는 국내 소형 어선의 재화상태에 따른 중량 및 무게중심 추정식을 제안하였다. 소형 어선에 탑재되는 중량물은 선원, 어구 등의 고정 중량과 연료, 청수, 식량, 미끼, 어획물 등의 가변 중량으로 분류할 수 있다. 다양한 소형 어선들의 중량 데이터를 통계 분석한 후, 각 탑재물의 중량 및 무게중심을 총톤수에 대하여 선형 함수화하였다. 그리고 재화상태를 고려하여 각 가변 중량물에 가중치를 부가하는 방식으로 총 중량 및 무게중심 추정식을 구성하였다. 소형 어선의 길이와 총톤수, 그리고 재화상태 정보만을 활용하여 총 중량 및 무게중심을 상당히 신뢰도 높게 추정할 수 있음을 검증하였다.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1998년도 춘계학술발표회논문집(2)
• /
• pp.154-159
• /
• 1998

In order to assess the susceptibility of the environmentally assisted cracking(EAC) on SA508 Cl.3 steel in primary water condition, potential step test and slow strain rate test(SSRT) were conducted in a simulated crack tip condition. In this test, anodic dissolution was dominant in the crack tip environments. Proposed simple dissolution model is a modification of Hishida's anodic dissolution model at the plastic zone. One can predict actual crack growth rate with the smooth specimen through this model.

• 대한본초학회지
• /
• 제26권1호
• /
• pp.97-101
• /
• 2011

Objectives : The purpose of this research is to identify the actual origin species imported as Aquilaria malaccensis from Indonesia. Methods : After producing the permanent preparat by cutting off the specimen thinly, we observed its characteristics. Results : The imported ones have not interxylary parenchyma, so none is in the genus aquilaria. Since the aliform parenchyma is mostly observed around the vessel pore, they are in the genus gonystylus, and the rest have no aliform parenchyma, so their specimen is unidentified. Conclusion : The imported as A. malaccensis are not in the genus aquilaria, but most of them are in the genus gonystylus and, for the rest, the specimen is unidentified.

• 대한기계학회논문집A
• /
• 제25권4호
• /
• pp.756-763
• /
• 2001

In the process of integrity evaluation for nuclear power plant components, a series of fracture mechanics evaluation on surface cracks in reactor pressure vessel(RPV) must be conducted. These fracture mechanics evaluation are based on stress intensity factor, K. However, under pressurized thermal shock(PTS) conditions, the combination of thermal and mechanical stress by steep temperature gradient and internal pressure causes considerably high tensile stress at the inside of RPV wall. Besides, the internal pressure during the normal operation produces high tensile stress at the RPV wall. As a result, cracks on inner surface of RPVs may experience elastic-plastic behavior which can be explained with J-integral. In such a case, however, J-integral may possibly lose its validity due to constraint effect. In this paper, in order to verify the suitability of J-integral, tow dimensional finite element analyses were applied for various surface cracks. A total of 18 crack geometries were analyzed, and $\Omega$ stresses were obtained by comparing resulting HRR stress distribution with corresponding actual stress distributions. In conclusion, HRR stress fields were found to overestimate the actual crack-tip stress field due to constraint effect.

• 한국가스학회지
• /
• 제12권2호
• /
• pp.69-76
• /
• 2008

2005년부터 최근까지 국내의 CNG버스 사고가 3건 보고되었다. 1차와 2차 사고의 원인은 용기 결함 및 관리 결함으로 밝혀졌고 3차 사고는 가스 누출에 의한 화재로 판명되었다. 3건의 사고의 근본원인을 분석하여 CNG 버스의 안전성을 확보하는 방안을 제안하였다. 또한 용기폭발의 파괴력을 이론적으로 계산하고, 피해결과 예측 프로그램(PHAST)의 결과와 비교 고찰하였다. 이론적으로는 120 l, 20MPa의 메탄용기가 폭발할 경우 최대 1.2 kg의 TNT 폭발에 해당하였으며 과압의 크기를 비교해 보면 피해결과예측 프로그램이 이론적인 계산보다 더 큰 값을 산정하는 것으로 나타났다. 그러나 실제 용기폭발의 피해는 이론적인 계산보다도 작았다. 성능기반설계 개념에 의해 설계된 CNG용기는 출고 후 성능시험이 기준대로 이루어졌는지 확인할 수 없는 단점이 있다. 용기의 인성 확보가 제대로 이루어지지 않으면 겨울철 새벽 운행시에 취성파괴에 취약할 수 있으며, 자긴 처리 압력이 적절하지 않으면 사용중 반복 충전에 의한 피로손상에 의해 균열이 발생할 가능성이 있다. 기존 사고의 CNG 저장용기의 파열에서 주는 중요한 교훈은 용기 폭발 직후에 화재로 전이되지 않았다는 점이다. 이는 천연가스의 확산이 매우 빨라 점화가 용이치 않기 때문으로 판단된다.

• 한국해양공학회지
• /
• 제28권5호
• /
• pp.423-428
• /
• 2014

Ice loads may be conveniently categorized as local ice loads and global ice loads. Local ice loads are often defined as ice pressures acting on local areas of shell plates and stiffeners. Therefore, local ice loads are defined in all ice class rules. However, directly measuring the local ice pressure using the actual ice class vessel is a very difficult task because appropriate instruments for direct measurement must be installed on the outer hull, and they are easily damaged by direct ice contacts/impacts. This paper focuses on the estimation of the local ice pressure using the data obtained from icebreaking tests in the Arctic sea in 2010 using the Korean icebreaking research vessel (IBRV) ARAON. When she contacted the sea ice, the local deformation of the side shell was measured by the strain gauges attached to the inside of the shell. Simultaneously, the contact area between the side shell and sea ice is investigated by analyzing the distribution of the measured strain data. Finally, the ice pressures for different contact areas are estimated by performing a structural analysis.