• Korean Chemical Engineering Research
• /
• v.61 no.1
• /
• pp.68-73
• /
• 2023

Smoke masks have attracted great interests and have been supplied widely for the improvement of the safety during fire evacuation. However, there is not sufficient research on the practical utility, certification status and easy-donning about commercial smoke masks, therefore it is difficult to determine the actual usefulness of the smoke masks. In this study, we conducted a survey on users' perceptions and experiences about the smoke masks, and investigated the status of certification of 54 commercial smoke masks. We also performed donning tests and examined degrees of discomfort for 4 types of the smoke masks. Although 22% of 235 respondents had experienced the smoke masks before the test, and 23% of the respondents did not know the smoke masks, 93% of the respondents expected that the smoke masks could protect users from fire smokes and toxic gases. It was found that 41% of the commercial smoke masks did not certify according to domestic or overseas performance standards. Most certification standards have not effectively regulated maximum wearing time for the smoke masks. Only ASTM E 2952 and KFIS 024 had specific standards for the maximum wearing time of 30 s. As a result of donning tests for 4 types of smoke masks, the wearing time of the hood-type mask and self-contained smoke mask exceeded 30 s, therefore these types of smoke masks might increase the required safe evacuation time. On the other hand, it was also found that short education about the donning could reduce the wearing time by 19% and numbers of improper wearing by 89%.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.4
• /
• pp.91-99
• /
• 2005

Flight compatibility certification is performed to substantiate the compatibility between ALQ-X ECM pod and KF-16D/RF-4C aircraft. A certification plan for the ALQ-X flight compatibility is established. Similarity analysis, mass/inertia analysis, structural analysis/test, and ground vibration test/flutter analysis are made to support the safety of MIL-HDBK-1763 Test 250 (Captive compatibility flight profile). Aircraft flew along flight envelope boundary with representative ALQ-X configurations. Handling qualities are evaluated by comparing flight characteristics of the aircraft with and without ALQ-X. Structural integrity and endurance is evaluated using measured flight test data. Results of these flight tests showed that ALQ-X is compatible with KF-16D/RF-4C without altering the flight envelope which has originally been certified for ALQ-88 and ALQ-119 ECM pods. ALQ-X certification program made following technical achievements: Type III certification for foreign designed fighter, flutter analysis program development using GVT results, and utilization of MIL-STD-1553B data bus in flight test.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.12
• /
• pp.1070-1079
• /
• 2012

The impact energy absorbing is a very important characteristic of an aircraft to enhance the survivability of occupants when an aircraft is under the survivable accident such as an emergency landing condition. The impact energy is generally transmitted into the occupant and absorbed through a landing gear, a subfloor (lower structure of fuselage), and a seat. The characteristic of crash energy absorbing of a subfloor depends on the type of an aircraft, a shape of structure, and an applied material. Therefore, the study of crashworthiness characteristics of a subfloor structure is very important work to improve the safety of an aircraft. In this study, a finite element model of a narrow body fuselage section for the 80~90 seats regional aircraft was developed and crash simulation was executed using an explicit finite element analysis. Through survey of the impact energy distribution of each structural part of a fuselage and floor-level acceleration response, the crashworthiness characteristics and performance was evaluated.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.7
• /
• pp.445-454
• /
• 2022

Ice accretion on the aircraft components, such as wings, fuselage, and empennage, can occur when the aircraft encounters a cloud zone with high humidity and low temperature. The prevention of ice accretion is important because it causes a decrease in the aerodynamic performance and flight stability, thus leading to fatal safety problems. In this study, a shape design optimization of a multi-element airfoil is performed to minimize the amount of ice accretion on the high-lift device including leading-edge slat, main element, and trailing-edge flap. The design optimization framework proposed in this paper consists of four major parts: air flow, droplet impingement and ice accretion simulations and gradient-free optimization algorithm. Reynolds-averaged Navier-Stokes (RANS) simulation is used to predict the aerodynamic performance and flow field around the multi-element airfoil at the angle of attack 8°. Droplet impingement and ice accretion simulations are conducted using the multi-physics computational analysis tool. The objective function is to minimize the total mass of ice accretion and the design variables are the deflection angle, gap, and overhang of the flap and slat. Kriging surrogate model is used to construct the response surface, providing rapid approximations of time-consuming function evaluation, and genetic algorithm is employed to find the optimal solution. As a result of optimization, the total mass of ice accretion on the optimized multielement airfoil is reduced by about 8% compared to the baseline configuration.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.31 no.2
• /
• pp.139-143
• /
• 2011

The problem of delamination of composite tubes by impact has been acknowledged in aerospace and automobile industry. Non-destructive testing(NDT) methods in composite material structure are important to evaluate reliability of composite structure. There are many kinds of NDT methods which can detect the inside defect of the composite material such as Infrared Thermography(IRT). Infrared thermal imaging of object is different from that of a defect, in heated composite tubes with an internal defect, and then location and size of a defect can be measured by the analysis of thermal imaging pattern. In this study, Lock-in Infrared thermography detect internal defects of Impacted composite tubes by the inspection of infrared lay radiated from the surface of composite tubes.

• The Journal of Bigdata
• /
• v.6 no.2
• /
• pp.29-38
• /
• 2021

Deviation of route in aviation safety management is a dangerous factor that can lead to serious accidents. In this study, the anomaly score is calculated by classifying the tracks through clustering and calculating the distance from the cluster center. The study was conducted by extracting tracks within 100 km of the airport from the ADS-B track data received for one year. The wake was vectorized using linear interpolation. Latitude, longitude, and altitude 3D coordinates were used. Through PCA, the dimension was reduced to an axis representing more than 90% of the overall data distribution, and k-means clustering, hierarchical clustering, and PAM techniques were applied. The number of clusters was selected using the silhouette measure, and an abnormality score was calculated by calculating the distance from the cluster center. In this study, we compare the number of clusters for each cluster technique, and evaluate the clustering result through the silhouette measure.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.2
• /
• pp.83-94
• /
• 2015

Recently, the necessity of spatial data in unaccessible area was challenged to set up various plans and policies for preparing the unification and the cooperative projects between South-North Korea. Therefore, this paper planned to evaluate the possibility of adopting the error tolerance in Geometric correction for 1/5,000 digital topographic mapping, using the PLEIADES images and the TerraSAR GCPs (Ground Control Points). The geometric correction was performed by changing the number and placement of GCPs by GPS (Global Positioning System) surveying, as the optimal placement of 5 GCPs were selected considering the geometric stability and steady rate. The positional accuracy evaluated by the TerraSAR GCPs, which were selected by optimal placement of GCPs. The RMSE in control points were X=±0.64m, Y=±0.46m, Z=±0.28m. While the result of geometric correction for PLEIADES images confirmed that the RMSE in control points were X=±0.34m, Y=±0.27m, Z=±0.11m, the RMSE in check points were X=±0.50m, Y=±0.30m, Z=±0.66m. Through this study, we believe if spatial data can integrate with the PLEIADES images and the optimal TerraSAR GCPs, it will be able to obtain the high-precision spatial data for adopting the regulation of 1/5,000 digital topographic map, which adjusts the computation as well as the error bound.

• Proceedings of the Safety Management and Science Conference
• /
• 1999.11a
• /
• pp.343-343
• /
• 1999

아크용접은 산업전반에 걸쳐 그 생산기반에 없어서는 안될 필수기술로써 자동차 및 조선, 항공우주산업에 이르기까지 경제기반에 미치는 파급효과가 매우 크다. 그러나 이 아크용접을 하게 되면 각종 가스와 미세입자로 이루어진 흄이 발생하게 되는데 이들은 작업자들의 건강에 많은 영향을 미치는 것으로 보고되어 있다. 용접흄에는 용접재료 및 용접공정에 따라 다양한 유해원소가 포함되어 있고 그 종류에 따라 인체에 미치는 잠재적 독성효과도 매우 광범위하다. 최근 국내에서는 용접사들 중에 용접흄에 포함된 중금속 중 Mn중독에 의한 파킨스씨병 환자들과 Cr중독에 의하여 콧속 연골에 구멍이 뚫리는 비중격천공(鼻中隔穿孔) 환자들이 직업병으로 판정 받아 산재요양이 승인된 사례가 있다. 이러한 계기로 인하여 용접사들의 용접기피 현상이 심화되고 작업환경에 대한 법적규제는 선진 외국뿐만 아니라 국내에서도 한층 엄격하게 강화되고 있는 실정이다. 따라서 이제는 작업자와 사용자 모두 용접흄에 대한 인식의 전환이 요구되는 때이며 여러 분야에서 이러한 용접흄에 대한 연구가 활발히 진행되어야 한다. 해외에서는 이미 용접흄에 대한 연구가 활발히 진행되어 왔으나 국내의 경우는 매우 미비한 상태이며 용접산업의 미래 영향력이나 필요성을 고려할 때 국내에서도 적극적인 관심을 가져야 할 부분으로 판단된다. 본 연구에서는 아크용접공정에서 발생하는 흄의 특정 중금속 성분이 인체에 치명적인 악영향을 미치는 것에 착안하여 여러 종류의 용접재료에서 발생되는 용접흄의 중금속 분포를 조사하여 비교하였다. 이것은 향후 용접재료별 및 용접공정별 발생되는 흄의 유해원소를 저감시킬 수 있고 또한 각종 유해원소의 노출기준 및 평가기준을 마련할 수 있는 기초data로써 도움이 되리라 사료된다.동, 공정중재고가 줄어드는 결과를 보였고, 가동률 수준이 높을수록 ORR 방법간의 차이가 크게 나타났다. 그리고 부하평준화 기능은 Order Release 정책의 유효성에 별 영향을 주지 않는 것으로 나타났다. 결론적으로, Order Release 방법은 우선순위규칙간의 성능차이를 줄이거나, 대체할 수 통제 기법이라기보다는 우선순위규칙을 보완하여 공정중재고와 작업현장에서의 리드타임, 리드타임의 편차를 줄여주는 역할을 한다고 볼 수 있다. 그리고, 계획시스템이 존재하여 계획오더가 일정기간간격으로 이송되는 환경에서 특히 유용하다는 결론을 얻었다. 알 수 있었다. 것인데, 제조업에서의 심각한 고비용, 저효율 문제 를 해결하기 위해 필수적으로 도입해야만 하는 실정이다. 또한 소비자의 다양한 요구로 인 하여 제품의 종류와 사양면에서 심한 변동을 보이는 시장 수요에, 신속한 정보처리로 대응 하는데도 크게 기여하고 있다. 이에 본 연구에서는, 자동차 Job Shop의 동기화 생산방식을 지원하는 동기화 생산시스템의 구축 모델을 제시하고자 한다.과로 여겨지며, 또한 혈청중의 ALT, ALP 및 LDH활성을 유의성있게 감소시키므로서 감잎 phenolic compounds가 에탄올에 의한 간세포 손상에 대한 해독 및 보호작용이 있는 것으로 사료된다.반적으로 홍삼 제조시 내공의 발생은 제조공정에서 나타나는 경우가 많으며, 내백의 경우는 홍삼으로 가공되면서 발생하는 경우가 있고, 인삼이 성장될 때 부분적인 영양상태의 불충분이나 기후 등에 따른 영향을 받을 수 있기 때문에 앞으로 이에 대한 많은 연구가 이루어져야할 것으로 판단된다.태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(min

• Journal of Korean Society of Disaster and Security
• /
• v.14 no.4
• /
• pp.29-36
• /
• 2021

Recently, due to climate change, the slope is increasing, and the risk of steep slope disasters such as the occurrence of slope collapse in the east coast and Busan region in 2019 and the Gokseong landslide in 2020 is increasing. Particularly, most national parks are made up of mountainous areas, and the risk of disasters on steep slopes is increasing. As the ground of the national park is aging and the weathering and jointing of the bedrock are accelerating due to climate change, the slope collapse and rockfall are increasing, and the annual number of visitors is increasing, it is necessary to manage steep slopes adjacent to multi-use facilities with many users. In this study, dangerous steep slopes that affect multi-use facilities in national parks were analyzed using GIS and verified through field surveys. As a process for extracting steep slopes adjacent to multi-use facilities in national parks, the slope was made in DEM and slopes of 34 degrees or higher were extracted. The difference between the maximum and minimum heights of the extracted slopes was used to confirm that the slopes met the standard for steep slopes, and the analysis of the slope direction was used to confirm whether it had an effect on the multi-use facilities. After that, precision aerial images and field photos were analyzed to finally identify risks at 4 sites, and field surveys were conducted. As a result of the field survey, all 4 sites were found to be steep slopes, 3 were graded D and 1 was graded C, so it was confirmed that management was required as a risk of collapse. All steep slopes extracted through GIS were found to be dangerous, so it is judged that the extraction of steep slopes through GIS would be appropriate.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.5D
• /
• pp.477-483
• /
• 2010

The existing mass transport system, with its limited capacity and the saturated road networks, has given cause for a new means of transport to be developed, and strong demands for such new means of transport are observed more than ever. However, the traffic authority is seeking a new transport system that focuses more on LRT(Light Rail Transit), a downsized version of the existing urban railroad, rather than one that is appropriate to solve the traffic problems. Moreover, local governments are experiencing difficulties in planning their own mass transportation(bus or urban railroad) as they have no specified criteria for selecting a mass transport system. Accordingly, there has been an increasingly loud voice that calls for criteria to determine which mass transport system befits each transportation corridor. This paper develops a mass-transport demand forecasting model based on the GIS Buffering analysis of each transportation corridor in the city, sets up the capacity for each mass transport system and presents the criteria for selecting an optimal mass transport system for each transportation corridor. It also presents a methodology that identifies necessary and sufficient conditions for selection and evaluation, since it is most important to select the optimal mass-transport system that can meet the demand by each mass-transportation corridor.