• Title/Summary/Keyword: accident in school

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Optimal Sensor Placement for Improved Prediction Accuracy of Structural Responses in Model Test of Multi-Linked Floating Offshore Systems Using Genetic Algorithms (다중연결 해양부유체의 모형시험 구조응답 예측정확도 향상을 위한 유전알고리즘을 이용한 센서배치 최적화)

  • Kichan Sim;Kangsu Lee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.37 no.3
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    • pp.163-171
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    • 2024
  • Structural health monitoring for ships and offshore structures is important in various aspects. Ships and offshore structures are continuously exposed to various environmental conditions, such as waves, wind, and currents. In the event of an accident, immense economic losses, environmental pollution, and safety problems can occur, so it is necessary to detect structural damage or defects early. In this study, structural response data of multi-linked floating offshore structures under various wave load conditions was calculated by performing fluid-structure coupled analysis. Furthermore, the order reduction method with distortion base mode was applied to the structures for predicting the structural response by using the results of numerical analysis. The distortion base mode order reduction method can predict the structural response of a desired area with high accuracy, but prediction performance is affected by sensor arrangement. Optimization based on a genetic algorithm was performed to search for optimal sensor arrangement and improve the prediction performance of the distortion base mode-based reduced-order model. Consequently, a sensor arrangement that predicted the structural response with an error of about 84.0% less than the initial sensor arrangement was derived based on the root mean squared error, which is a prediction performance evaluation index. The computational cost was reduced by about 8 times compared to evaluating the prediction performance of reduced-order models for a total of 43,758 sensor arrangement combinations. and the expected performance was overturned to approximately 84.0% based on sensor placement, including the largest square root error.

Analysis of Safety Education Contents of 『Field of home life』 in Technology·Home Economics Textbook developed by the revised curriculum in 2009 (2009 개정 기술·가정 교과서 『가정생활영역』의 안전교육 내용 분석)

  • Kim, Nam Eun
    • Journal of Korean Home Economics Education Association
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    • v.29 no.2
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    • pp.23-39
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    • 2017
  • The Purpose of this study is to present the basic data for selecting and improving the safety education contents which help practically middle school students through analysis of contents of safety education in 'field of home life' of 2009 revised middle school textbooks. The subjects of analysis are 12 types of middle school textbooks: in total 24 books written by 12 publishers in terms of the revised curriculum in 2009. The analysis criteria is developed by the researcher referring to preceding studies regarding safety education based on the seventh safety education standard presented by the Ministry of Education (2015). With such analysis criteria, all words related to the contents of the safety education of analysis criteria were extracted from each textbook, such as words directly mentioned as 'safety', words mean as 'psychological safety' and 'happy life', words related to 'attention', 'note', 'stability' etc. Under the analytic frame of safety education contents according to a home economics textbook, content analysis method was used for producing the frequency and percent of those words. The textbook analysis shows that the number of pages regarding safety education is 336.3 pages, as 9.8% in total 3,412 pages of 12 types of technology and home economics textbooks. As following the analysis of each textbook volume of the proportion in the contents related to safety education, 224.9 pages are on the first volume and 111.9 pages are on the second volume. As grades increase from year one to year three, the proportion of safety education in home economics textbooks is decreased. The highest number of safety education contents unit is 'Self-management of youth' which includes three parts of safety education. In the case of a unit for emphasizing practice, experience and practical exercise such as 'Life of youth' and 'Practice of eco-living', safety education content in the area of 'life safety' are mostly contained. Safety accidents related to the most student experienced, Household accidents (1.4%) and experiment or practice accidents (0.3%) are presented in a low figure. The contents of universal housing and school violence are duplicated on first and second volume of text. The most presented safety education content in the 12 types of textbooks are proper sexual attitude, dietary problems, family conflict and food choice. The least common contents are dangerous drugs, family welfare, internet addiction and industrial accident compensation insurance. As this study is to analyze 12 textbooks developed in 2009 revision curriculum, it is necessary to compare it with the textbook written by the revised curriculum in 2015 and to clarify the contents system of safety education and to avoid duplication of contents. In addition, it is necessary to develop and distribute a safety education program that can support textbooks.

Convergence Effective Factors for Work Performance among Returning to Workers with Industrial Accident (산업재해 직업복귀자의 업무수행능력 융합적 영향 요인)

  • Kim, Chae-Bong;Yang, Jeong-Hee;Choi, Bo-Ram;Han, Seong-Min
    • Journal of the Korea Convergence Society
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    • v.7 no.3
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    • pp.149-157
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    • 2016
  • For workers, industrial accidents exert a bad effect on the productivity, quality of life, and depress the morale. This study aimed to examine the overall influence on job performance of employees who returned to work after industrial accidents. This was a cross-sectional study using the data of 2013 and 2014 Panel Study of Worker's Compensation Insurance (PSWCI), and we performed logistic-regression analysis to analyze an affinity between general characteristics and job performance as independent variable and outcome variable, respectively. As a result, the major factor depressed the job performance were the 1 - 7 degree of disabilities and injuries with convalescence period for 6 to 9month or more than 12 months. In other words, this study shown that job performance was decreased as higher degree of disability and longer convalescence period. Job performance is the factor to identify indirectly worker's successful return to work, and it is important in follow-up of workers who returned to work after industrial accidents. Stable job performance of an industrial disaster victim is the key factor to maintain worker's comfortable and qualitative life as well as increase of productive capacity.

A study on the explosion proof by the electric discharge on voltage application type (전압인가식 제전기의 방폭화에 관한 연구)

  • Lee Chun Ha;Kim Jum Ho;Park Min Young
    • Journal of the Korean Institute of Gas
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    • v.8 no.4 s.25
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    • pp.62-69
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    • 2004
  • It is necessary to eliminate the electric static for the prevention of disasters by electric static discharge, the improvement of production efficiency, the protection of a sensitive electronic devices in the variable manufacturing processes. Then it is handled for elimination of electric static in the painting plant, the film manufacturing plant, the producing semi-conductor factory. This study described on the ideal condition of electric static elimination efficiency by changing of the length of voltage input type eliminator's bar, the length of copper pipe and the gap of electrode and the existence of explosion by inflammable gas with that conditions. As the result, the electric static elimination efficiency has the most ideal value at the 8-11(mm) gap of the earth electrode and needle type electrode each elimination bar and there is not explode at the explosive experiment of inflammable gas with the ideal elimination bar. We can consider that there are some data which are needed for elimination efficiency and it will be able to protect the occurrence of explosion accident inflammable nas in the industrial fields.

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Clinicopathologic Characteristics of Stage IV Early Gastric Cancer (IV기 조기위암의 임상병리학적 특성)

  • Kim, Min Kuk;An, Ji Yeong;Choi, Min Gew;Noh, Jae Hyung;Sohn, Tae Sung;Kim, Sung
    • Journal of Gastric Cancer
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    • v.8 no.3
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    • pp.136-140
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    • 2008
  • Purpose: Stage IV early gastric carcinoma (EGC) is a rare disease. We report here on 10 cases of EGC that showed metastasis in more than 15 lymph nodes. Materials and Methods: A total of 8354 cases of gastric carcinoma in patients who underwent surgical procedures between January 2001 and January 2007 at Samsung Medical Center were studied, and 10 cases were classified as stage IV EGC. We investigated their clinicopathologic characteristics. Results: There were 5 males and 5 females. Their ages at operation ranged from 46 to 76 years with a mean age of 61. All of the 10 patients had undergone curative resection for gastric cancer. The pathological diagnosis confirmed that all of the patients had tumor confined to the submucosa. The median size of the tumors was 5.3cm and the mean number of dissected nodes was 45.5 with a mean number of 22.2 involved nodes. Six cases were classified as the diffuse type and 4 were classified as the intestinal type by Lauren's classification. Histologically, 3 cases were signet ring cell carcinoma, 3 were poorly differentiated, 2 were moderately differentiated and 2 were well differentiated adenocarcinoma. Endolymphatic invasion was found in 9 cases. The median follow-up was 31 months. Adjuvant chemotherapy was done in 9 patients, and the patient who did not receive chemotherapy died by cerebrovascular accident. 2 patient had recurrence of gastric cancer and 7 survived without recurrence. Conclusion: More cases should be collected and further studies on the molecular and cellular tumor characteristics are required to characterize these tumors that show aggressive lymphatic spread.

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The Relationship between Bone Bruise in MRI and Associated Injuries after the Knee Joint Trauma (슬관절 외상 후 자기 공명 영상에서 관찰되는 잠재성 골 병변과 동반 손상과의 관계)

  • Kyung Hee-Soo;Ihn Joo-Chul;Kim Poong-Taek;Oh Chang-Wug;Yeo Jun-Young
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.1 no.1
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    • pp.89-96
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    • 2002
  • Purpose : The purpose is to analyze the relationship between bone bruise in MRI and associated injuries after the knee joint trauma. Materials and Methods : Total 50 cases were reviewed, divided into two groups according to initial trauma energy. High-energy group (group I), such as traffic accident was 13 cases, low-energy group (group II), such as sports trauma was 37 cases. The type of the lesion was used the classification by Costa-Paz. The site of lesion was analyzed according to femoral/tibial, medial/lateral and anterior/middle/posterior site respectively. Associated injuries were confirmed by physical examination, radiograph, MRI and arthroscopy. Results : In group I there was a various distribution of the bone bruise in the knee joint according to mechanism of injury. The bone bruise with ACL injury was 38$\%$ only and the most frequent type was Costa-Paz type I (52.6 $\%$). In group II more frequent locations were the middle portion of the lateral femoral condyle and the posterior portion of the lateral tibial condyle. Bone bruise associated with ACL injury, was upto 56.8 $\%$ and the frequent type were Costa-Paz type II (48 $\%$), in order type I (42 $\%$). As a result, in the high-energy injury the bone bruise had a various location in both condyle and less frequently associated injury, but in the low-energy injury there was particularly frequent location of bone bruise, associated injury and type. Conclusions : We could assess the associated injury by analysis of the location and type of bone bruise, especially in the low-energy injury, e.g. sports injury. But further study will be necessary with more case analysis.

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The Prediction of Export Credit Guarantee Accident using Machine Learning (기계학습을 이용한 수출신용보증 사고예측)

  • Cho, Jaeyoung;Joo, Jihwan;Han, Ingoo
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.83-102
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    • 2021
  • The government recently announced various policies for developing big-data and artificial intelligence fields to provide a great opportunity to the public with respect to disclosure of high-quality data within public institutions. KSURE(Korea Trade Insurance Corporation) is a major public institution for financial policy in Korea, and thus the company is strongly committed to backing export companies with various systems. Nevertheless, there are still fewer cases of realized business model based on big-data analyses. In this situation, this paper aims to develop a new business model which can be applied to an ex-ante prediction for the likelihood of the insurance accident of credit guarantee. We utilize internal data from KSURE which supports export companies in Korea and apply machine learning models. Then, we conduct performance comparison among the predictive models including Logistic Regression, Random Forest, XGBoost, LightGBM, and DNN(Deep Neural Network). For decades, many researchers have tried to find better models which can help to predict bankruptcy since the ex-ante prediction is crucial for corporate managers, investors, creditors, and other stakeholders. The development of the prediction for financial distress or bankruptcy was originated from Smith(1930), Fitzpatrick(1932), or Merwin(1942). One of the most famous models is the Altman's Z-score model(Altman, 1968) which was based on the multiple discriminant analysis. This model is widely used in both research and practice by this time. The author suggests the score model that utilizes five key financial ratios to predict the probability of bankruptcy in the next two years. Ohlson(1980) introduces logit model to complement some limitations of previous models. Furthermore, Elmer and Borowski(1988) develop and examine a rule-based, automated system which conducts the financial analysis of savings and loans. Since the 1980s, researchers in Korea have started to examine analyses on the prediction of financial distress or bankruptcy. Kim(1987) analyzes financial ratios and develops the prediction model. Also, Han et al.(1995, 1996, 1997, 2003, 2005, 2006) construct the prediction model using various techniques including artificial neural network. Yang(1996) introduces multiple discriminant analysis and logit model. Besides, Kim and Kim(2001) utilize artificial neural network techniques for ex-ante prediction of insolvent enterprises. After that, many scholars have been trying to predict financial distress or bankruptcy more precisely based on diverse models such as Random Forest or SVM. One major distinction of our research from the previous research is that we focus on examining the predicted probability of default for each sample case, not only on investigating the classification accuracy of each model for the entire sample. Most predictive models in this paper show that the level of the accuracy of classification is about 70% based on the entire sample. To be specific, LightGBM model shows the highest accuracy of 71.1% and Logit model indicates the lowest accuracy of 69%. However, we confirm that there are open to multiple interpretations. In the context of the business, we have to put more emphasis on efforts to minimize type 2 error which causes more harmful operating losses for the guaranty company. Thus, we also compare the classification accuracy by splitting predicted probability of the default into ten equal intervals. When we examine the classification accuracy for each interval, Logit model has the highest accuracy of 100% for 0~10% of the predicted probability of the default, however, Logit model has a relatively lower accuracy of 61.5% for 90~100% of the predicted probability of the default. On the other hand, Random Forest, XGBoost, LightGBM, and DNN indicate more desirable results since they indicate a higher level of accuracy for both 0~10% and 90~100% of the predicted probability of the default but have a lower level of accuracy around 50% of the predicted probability of the default. When it comes to the distribution of samples for each predicted probability of the default, both LightGBM and XGBoost models have a relatively large number of samples for both 0~10% and 90~100% of the predicted probability of the default. Although Random Forest model has an advantage with regard to the perspective of classification accuracy with small number of cases, LightGBM or XGBoost could become a more desirable model since they classify large number of cases into the two extreme intervals of the predicted probability of the default, even allowing for their relatively low classification accuracy. Considering the importance of type 2 error and total prediction accuracy, XGBoost and DNN show superior performance. Next, Random Forest and LightGBM show good results, but logistic regression shows the worst performance. However, each predictive model has a comparative advantage in terms of various evaluation standards. For instance, Random Forest model shows almost 100% accuracy for samples which are expected to have a high level of the probability of default. Collectively, we can construct more comprehensive ensemble models which contain multiple classification machine learning models and conduct majority voting for maximizing its overall performance.

A Fundamental Study on the Improvements of Speed Limit at the Ports and Fairways in Korea (항만과 수로의 제한속력 개선방안에 관한 기초 연구)

  • Kim, Deug-Bong;Yun, Byeong-Won;Jeong, Jae-Yong;Park, Jin-Soo;Park, Young-Soo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.18 no.5
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    • pp.423-430
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    • 2012
  • The purpose of Speed limit at sea is to keep harbor calmness, to maintain efficient traffic flow and to prevent maritime accidents. The Korean Regional Maritime Affairs and Port Office(KRMAPO) specified and enforced the ship's speed limits at the 19 harbors around the Korean coasts. However, problems have been raised to the adequacy of speed limits. This paper made a research on the speed limit set standards, analyzed vessel traffic survey and the dilemma on the specified speed limits imposed by KRMAPO. The result of this study has shown an overall average of 48 % violation rate on speed limit with passenger ships and large vessels of more than 5,000 tons having higher violation rate. Average speed was higher than the limit speed in some harbors and deviation of 4.2 to 5.2 knots was investigated. Further, harbors having higher average speed also have higher deviation accident incidence. Therefore, this paper had confirmed that there is a need for institutional review and improvement of Korea's port and fairways speed traffic management.

A Study on the Sea-sickness Susceptibility of Seafarer at the Wheel House and Engine Room (조타실과 기관실 근무자의 뱃멀미 민감성에 대한 연구)

  • Kim, Deug-Bong;Kim, Bu-Gi;Rim, Geung-Su;Kim, Hong-Ryoel;Kim, Chang-Su
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.1
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    • pp.42-48
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    • 2014
  • Seasickness not only makes persons on board vessels to vomit but also causes vertigo, headache, sleepiness, fatigue, lethargy and other discomforts. This ailment leads to disturbance of biorhythm and decline of perception which would eventually cause reduction of situational awareness among ship's operators that leads to marine accident. This study is about the sensitivity of people onboard ships to seasickness and focused on deck or navigation officer cadets(apprentice officers) and engine officer cadets(apprentice engineers) who have no previous experiences on board. It is conducted by using motion sensor that can measure ship's X, Y, Z-axis motions and through the questionnaire survey, and evaluated each students' degree of seasickness symptoms. Through this study, in same circumstance, we have known that there are different degrees of motion sickness for wheel house worker and engine room worker, It also confirmed that seasickness have high relationship with degree of hull motion and also, with cycle of hull motion. In addition, we have confirmed that Z-axis hull movement has higher relationship with seasickness than X-axis and Y-axis hull movements. This study aims to initiate additional researches about X-axis and Y-axis of the ship's motion which it expects to greatly enhance safety of wheelhouse and engine room personnel, ship's livability and comfortable sailing.

The Main Contents and Task in Future for the Air Transport Law Established Newly in the Korean Revised Commercial Law

  • Kim, Doo-Hwan
    • The Korean Journal of Air & Space Law and Policy
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    • v.27 no.1
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    • pp.75-101
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    • 2012
  • As the Reublic of Korea revised the Commercial Code including 40 articles of air transport enacted newly on May 23, 2011, so Korea became first legislative examples in the Commercial Code of the developed and developing countries. I would like to explain briefly the main contents of my paper such as (1) history of enacting newly Part VI (air transport) in the Korea's revised commercial law, (2) legal background enacting newly Part VI (air transport) in the Korea's revised commercial law and the problems on the conditions of air transport, (3) every countries' legislative examples on the civil liability of aircraft's operator, (4) unlawful Interference Convention and general risk convention of 2009, (5) main contents and prospects of the revised Commercial Code for the liability of aircraft's operator etc as the followings. Meanwhile as the Aviation Act, Commercial Code and Civil Code in Korea and Japan did not regulated at all the legal basis of solution on the disputes between victims and offender for the amount of compensation for damage due to personal or property damage caused by aircraft accidents in Korea and Japan, so it has been raised many legal problems such as protection of victims, standard of decision in trial in the event of aircraft accident's lawsuit case. But the Korean Revised Commercial Code including Part VI, air transport regulations was passed by the majority resolution of the Korean National Assembly on April 29, 2011 and then the South Korean government proclaimed it on May 23 same year. The Revised Commercial Code enforced into tothe territory of the South Korea from November 24, 2011 after six month of the proclaimed date by the Korean Government. Thus, though Korean Commercial Code regulated concretely and respectively the legal relations on the liability of compensation for damage in the contract of transport by land in it's Part II (commercial activities) and in the contract of transport by sea in its Part V (marine commerce), but the Amended Commercial Act regulated newly 40 articles in it's Part VI (air transport) relating to the air carrier's contract liability on the compensation for damage caused by aircraft accidents in the air passengers and goods transport and aircraft operator's tort liability on compensation for damage caused by the sudden falling or collision of aircraft to third parties on the surface and so it was equipped with reasonable and unified system among the transport by land, marine and air. The ICAO adopted two new air law conventions setting out international compensation and liability rules for damage caused by aircraft to third parties at a diplomatic conference hosted by it from April 20 to May 2, 2009. The fight against the effects of terrorism and the improvement of the status of victims in the event of damage to third parties that may result either from acts of unlawful interference involving aircraft or caused by ordinary operation of aircraft, forms the cornerstone of the two conventions. One legal instrument adopted by the Conference is "the Convention on Compensation for Damage to Third Parties, Resulting from Acts of Unlawful Interference Involving Aircraft" (Unlawful Interference Convention). The other instrument, "the Convention on Compensation for Damage Caused by Aircraft to Third Parties" (General Risk Convention), modernizes the current legal framework provided for under the 1952 Rome Convention and related Protocol of 1978. It is desirable for us to ratify quickly the abovementioned two conventions such as Unlawful Interference Convention and General Risk Convention in order to settle reasonably and justly as well as the protection of the South Korean peoples.

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