• Title/Summary/Keyword: Impact Force

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Estimation of the Impact of the Inclusion of Sharks in the Appendices of the 'Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)' on Korean Fisheries and Recommendations of the Domestic Measures on the Trade of the Listed Shark Species ('멸종위기에 처한 야생 동식물의 국제거래에 관한 협약'의 상어류 등재가 한국 수산업에 끼칠 영향과 대응 전략)

  • Sohn, Hawsun;An, Du Hae;Kim, Doo Nam;Lee, Sung Il;Park, Kyum Joon
    • Journal of Fisheries and Marine Sciences Education
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    • v.26 no.6
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    • pp.1278-1295
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    • 2014
  • The Sixteenth Meeting of the Conferences of Parties of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which was held in March 2013 in Bangkok, Thailand, listed five shark species and one genus, and uplisted one sawfish species. All new species listings will be come into force of the eighteen months delay, on the fourteenth of September, 2014. The purpose of the delay is to support the preparation of the domestic measures on shark trade by the parties, as there has been no previous experience in trading the commercially exploited aquatic species in the CITES. The CITES Secretary-General has visited several potential shark trade countries to encourage and facilitate the implementation of the new CITES listings. The newly listed sharks have been caught as a target or non-target species by Korean distant water fisheries and introduced into Korea. So the establishment or change of the domestic laws, regulations, and measures for the implementation of the new CITES species must be prepared before the effective entry date. This paper is prepared to assess the effects of the trade of the CITES listed shark species, and to suggest effective government service measures for the management of Korean distant water fisheries. The Ministry of Environment (MOE) is the general Management Authority of the CITES, and the Ministry of Food and Drug Safety (MFDS) is in charge of the medical trade of CITES listed species in Korea. By law, all imported medicines and medical materials must be inspected by the MFDS during the customs examination; this kind of authority sharing is reasonable and effective way of providing government service. Similarly, the designation of new CITES Management Authority for the trade of commercially exploited aquatic CITES species is critical and the Ministry of Oceans and Fisheries (MOF), which is now in charge of the trade of fisheries products, is the most appropriate governing body for this purpose in Korea. The revision of the National Plan of Action for Conservation and Management of Sharks, initially submitted to the Food and Agriculture Organization (FAO) of the United Nations in 2011 as a practical guideline for shark conservation in all Korean fisheries, could be a effective measure to achieve unification of conservation of endangered species and sustainable use of fisheries stocks. The proper CITES measures for the trade of listed species, such as the establishment of the documenting system for Non-detriment Findings, domestic measures suitable for the "Introduction from the Sea" clause, species specific Harmonized System Codes for the customs service, and an effective shark catch data reporting system should be in place prior to the fourteenth of September 2014.

A Study on Stress and Deformation through Finite Element Analysis of 2NC Head Processing Controlling AC Axis during 5-Axis Cutting Machine Training in the 4th Industrial Revolution of Machine Tool System (공작기계의 4차 산업혁명에서 5축 절삭가공기 교육 중 AC축을 제어하는 2NC 헤드 가공상의 유한요소 해석으로 응력 및 변형에 관한 연구)

  • Lee, Ji Woong
    • Journal of Practical Engineering Education
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    • v.13 no.2
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    • pp.327-332
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    • 2021
  • Materials used for education include SM20C, Al6061, and acrylic. SM20C materials are used a lot in certification tests and functional competitions as carbon steel, but they are also used in industrial sites. Al6061 is said to be a material that produces a lot of tools because it has lower hardness than carbon steel and is highly flexible. When practical guidance is given to students using acrylic materials, it is a material that causes vibration and tool damage due to excessive cutting. In this process, we examine how impact on the 5-axis equipment 2NC head can affect precision control. The weakest part of a five-axis equipment is the head that controls the AC axis. In the event of precision and cumulative tolerances in this area, the precision of all products is reduced. Thus, a key part of the 2NC head, the spindle housing was carried out using Al7075 T6 (U.S. Alcoasa) material and the entire body using FCD450 (spherical graphite cast iron). In the vibration and cutting process acting on these two materials, the analysis was carried out to determine the value of applying the force as a finite element analysis under extreme conditions. We hope that using these analytical data will help students see and understand the structure of 5-axis machining rather than 5-axis cutting.

Method for evaluating the safety performance and protection ability of the mobile steel protective wall during the high-explosive ammunition test (고폭탄 탄약시험 간 이동형 강재 방호벽의 안전성능 판단 및 유효 방호력 평가 방법)

  • Jeon, In-Beom
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.6
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    • pp.573-582
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    • 2021
  • In this study, a series of processes for evaluating the effective protection against barriers that should be equipped in institutions that perform reliability tests on high-risk ammunition, such as high-explosive ammunition, were introduced. The impact that high-explosive bombs can have on personnel includes damage to the eardrum and lungs caused by explosion overpressure and penetrating wounds that can be received by fragments generated simultaneously with the explosion. Therefore, a high-explosive with COMP B explosives as its contents were set up, and an explosion protection theory investigation to calculate the degree of damage, numerical calculations and simulations were performed to verify the protection power. A numerical calculation revealed the maximum explosion overpressure on the protective wall when the high-explosive exploded and the penetration force of the fragment against a 50 mm-thick protective wall to be 77.74 kPa and 41.34 mm, respectively. In the simulation verification using AUTODYN, the maximum explosion overpressures affecting the firewall and personnel were 56.68 kPa and 18.175 kPa, respectively, and the penetration of fragments was 35.56 mm. This figure is lower than the human damage limit, and it was judged that the protective power of the barrier would be effective.

Impacts of Minijob on Women's Employment in Germany (독일 미니잡이 여성 고용에 미친 영향)

  • Kang, Su-Dol
    • Korean Journal of Labor Studies
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    • v.23 no.2
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    • pp.277-306
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    • 2017
  • This article empirically explores the impact of minijobs in the wake of the Hartz reform in Germany on women's employment relationship. Theoretically it is of great significance to examine whether the minijobs play an active role as a bridge in leading the minijobbers to regular, socially secured jobs or not. Several interviews as well as secondary data I could get during my sabbatical in 2015 were used to test the theory. One of the main findings was the fact that the minijob labor market opened doors wide for women in Germany, particularly for career-interrupted women, students or pensioners. However, the minijob can easily become a trap of lowest income and poverty for women. Most women minjobbers cannot go over to regular, socially secured jobs. Especially in terms of collective industrial relations, it considerably damages the power of industrial unions and the legal binding force of collective agreement. In conclusion, this study makes it clear that the labor market segmentation theory rather than the transitional labor market theory is valid in accounting for the reality of minijob in Germany. In other words, the minijob in Germany has a Toijan Horse Effect. It also suggests, from a practical viewpoint, that German industrial unions or works councils organize the minijobbers and that the coverage of collective agreements be extended to the minijobbers. Consequently, the time-selective part-timer model put into practice in Korea in 2014 is not only invalid but also undesirable.

Effect of Hypersonic Missiles on Maritime Strategy: Focus on Securing and Exploiting Sea Control (극초음속 미사일이 해양전략에 미치는 영향: 해양통제의 확보와 행사를 중심으로)

  • Cho, Seongjin
    • Maritime Security
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    • v.1 no.1
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    • pp.241-271
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    • 2020
  • The military technology currently receiving the most attention is the hypersonic missile. hypersonic is faster than the speed of sound or Mach 5+. The vast majority of the ballistic missiles that it inspired achieved hypersonic speeds as they fell from the sky. Rather than speed, today's renewed attention to hypersonic weapons owes to developments that enable controlled flight. These new systems have two sub-varieties: hypersonic glide vehicles and hypersonic cruise missiles. Hypersonic weapons could challenge detection and defense due to their speed, maneuverability, and low altitude of flight. The fundamental question of this study is: 'What effect will the hypersonic missile have on the maritime strategy?' It is quite prudent to analyze and predict the impact of technology in the development stage on strategy in advance. However, strategy is essential because it affect future force construction. hypersonic missiles act as a limiting factor in securing sea control. The high speed and powerful destructive power of the hypersonic missile are not only difficult to intercept, but it also causes massive ship damage at a single shot. As a result, it is analyzed that the Securing sea control will be as difficult as the capacity of sea denial will be improved geographically and qualitatively. In addition, the concept of Fortress Fleet, which was criticized for its passive strategy in the past, could be reborn in a modern era. There are maritime power projection/defence, SLOC attack/defence in exploiting sea control. The effects of hypersonic missiles on exploiting sea control could be seen as both limiting and opportunity factors.

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A Study on the Buckling Stability due to Lateral Impact of Gas Pipe Installed on the Sea-bed (해저면에 설치된 가스관의 외부충격에 의한 좌굴 안전성 검토)

  • Park, Joo-Shin;Yi, Myung-Su
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.2
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    • pp.414-421
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    • 2022
  • Subsea oil and gas exploration is increasingly moving into deeper water depths, and typically, subsea pipelines operate under high pressure and temperature conditions. Owing to the difference in these components, the axial force in the pipe is accumulated. When a pipeline is operated at a high internal pressure and temperature, it will attempt to expand and contract for differential temperature changes. Typically, the line is not free to move because of the plane strain constraints in the longitudinal direction and soil friction effects. For a positive differential temperature, it will be subjected to an axial compressive load, and when this load reaches a certain critical value, the pipe may experience vertical (upheaval buckling) or lateral (snaking buckling) movements that can jeopardize the structural integrity of the pipeline. In these circumstances, the pipeline behavior should be evaluated to ensure the pipeline structural integrity during operation in those demanding loading conditions. Performing this analysis, the correct mitigation measures for thermal buckling can be considered either by accepting bar buckling but preventing the development of excessive bending moment or by preventing any occurrence of bending.

Analysis of Tree Roughness Evaluation Methods Considering Depth-Dependent Roughness Coefficient Variation (수심별 조도계수 변화를 고려한 수목 조도공식 특성 분석)

  • Du Han Lee;Dong Sop Rhee
    • Ecology and Resilient Infrastructure
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    • v.10 no.3
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    • pp.51-63
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    • 2023
  • Riverine tree management is crucial in realizing a balance between flood control and ecological preservation, which requires an accurate assessment of the impact of trees on river water elevations. In this study, eight different formulas for evaluating vegetation roughness considering the drag force acting on trees, were reviewed, and the characteristics and applicability of these methods were evaluated from a practical engineering perspective. The study compared the characteristics of vegetation roughness measurement methods for calculated roughness coefficients at different water depths and analyzed factors such as effects of tree canopy width, tree density and diameter, and tree stiffness coefficient, and water level estimation results. A comparison of roughness coefficients at the same water depths revealed that the Kouwen and Fathi-Moghadam formulas and the Fischenich formula yield excessive drag coefficients compared to other formulas. Factors such as channel geometry, tree diameter, and tree density showed varying trends depending on the formula but did not exhibit excessive outliers. Formulas considering the tree stiffness coefficient, such as the Freeman et al.'s formula and the Whittaker et al.'s formula, showed significant variations in drag coefficients depending on the stiffness coefficient. When applied to small- and medium-sized virtual rivers in South Korea using the drag coefficient results from the eight formulas, the results indicated a maximum increase in water level of approximately 0.2 to 0.4 meters. Based on this review, it was concluded that the Baptist et al., Huthoff et al., Cheng, Luhar, and Nepf's formulas, which exhibit similar characteristics and low input data uncertainties, are suitable for practical engineering applications.

A Study on the Impact of Prejudice and Environmental Factors on Entrepreneurship Intention: Mediating Role of Fear of Failure (편견과 환경요인이 창업 의지에 미치는 영향에 관한 연구: 실패두려움의 매개효과)

  • Lee, Ji Youn;Jeong, Chan Gu
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.5
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    • pp.141-157
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    • 2023
  • Start-ups are the driving force of economic development and play an important role in improving national competitiveness. The country's start-up support policies are increasing every year, but indicators that do not challenge them and do not consider future start-ups can predict employment reduction and unemployment can increase further. You can. The increase in the number of young people doing nothing is causing economic hardship and neglect of future precious human resources, which calls for a more realistic national entrepreneurship policy. Accordingly, this study sought to identify bias and environmental factors in order to reveal factors that influence the will to start a business among potential entrepreneurs in Korea. For this purpose, descriptive statistical analysis was performed using SPSS on a sample of 227 responses from the general public who are potential entrepreneurs interested in starting a business. As a result, prejudice decreased the will to start a business and increased fear of failure. On the other hand, the entrepreneur's environmental factors reduced the fear of failure and increased the will to start a business. Lastly, fear of failure was found to play a mediating role between the two independent variables and the will to start a business. The results of this study showed that prejudice was a negative factor in the will to start a business, and the environment was a positive factor. These research results suggest that in order to revitalize entrepreneurship, positive environmental factors that can provide entrepreneurs' correct recognition and support for entrepreneurship are necessary.

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A Study on the Moderating Effect of Perceived Voluntariness in the Organizational Information System Usage and Performance (정보시스템 사용과 성과에 있어서 자발성의 조절효과에 관한 연구)

  • Lee, Seung-Chang;Lee, Ho-Geun;Jung, Chang-Wook;Chung, Nam-Ho;Suh, Eung-Kyo
    • Asia pacific journal of information systems
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    • v.19 no.2
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    • pp.195-221
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    • 2009
  • According to an industry report, a large number of organizations have invested in Organizational Information System(OIS) in the past few years. Several research results indicate that successful investments in OIS lead to productivity enhancement, while failed ones result in undesirable consequences such as financial losses and dissatisfaction among employees. In spite of huge investments, however, many organizations have failed in achieving the hoped-for returns from OIS. Thus, understanding user acceptance, adoption, and usage of new IS(Information Systems) is an important issue for IS practitioners. Indeed, study of the user acceptance of new information system has been one of the most important research topics in the contemporary IS literature. Several theoretical models are tested to examine 'user acceptance' and 'usage behavior' in IS context. While many research models incorporate 'ease of use' or 'usefulness' as important factors in explaining user acceptance, Technology Acceptance Model(TAM) has been one of the most widely applied models in user acceptance and usage behavior. Even in recent IS studies that employ theories of innovation diffusion in the area of IS implementation, a major focus has been on the user's perception of information technologies. In this research, we study 'voluntariness' as an important factor in IS acceptance by users. Voluntariness is defined as "the degree to which the use of the innovation is perceived as being voluntary, or of free will" When examining the diffusion of accepting OIS, a thoughtful consideration should be given to 'perceived voluntariness.' Current article has following research questions: 1) What models are appropriate to explain the success of OIS? and 2) How does the 'voluntariness' affect the success of OIS? In order to answer these questions, a research model is proposed to describe the detailed nature of association among three independent variables (IT usage level, task interdependency, and organizational support), a mediating variable (IS usage), a dependent variable (perceived performance), and a moderating variable(perceived voluntariness). The central claim of this article is that organizations hardly realize expected returns from OIS investments unless perceived voluntariness is effectively managed after operating OIS. As an example of OIS in this study we have selected the Intranet of Republic of Korea Air Force (ROKAF). ROKAF has implemented the Intranet in an attempt to improve communication and coordination within the organization. To test our research model and hypotheses, survey questionnaires were first sent out to 400 Intranet users. With the assistance of ROKAF, Intranet users were initially identified among its members, and subjects were randomly drawn from the pool. 377 survey responses were finally returned. The unit of measurement and analysis in this research is a personal level. Path analysis based on structural equation modeling was used to test research hypotheses. Construct validity represents accordance between the theoretical base concept of constructs and its measurement items. Tests for the reliability and discriminant validity are accepted, thus verifying our survey instrument. In this research, we have proposed a conceptual framework to highlight the importance of perceived voluntariness after organization deploys OIS. The results of our analysis present several key finding. First, all three independent variables (IT usage level, task interdependency, and organizational support) have significant effects on IS usage, which will eventually improve performance. Thus, IS usage plays a mediating role between antecedent variables (IT usage level. task interdependency, and organizational support) and performance improvement. Second, the effect of the task dependency was the highest for IS usage among the three antecedent variables. This is highly plausible since one of the Intranet's major capabilities is to facilitate communication among members within an organization. Accordingly, we conclude that the higher the task dependency, the higher Intranet usage. The effect of user's IT usage level was the second, while the effect of the organizational support was the third. Finally, the perceived voluntariness plays a pivotal role in enhancing perceived performance in personal level after launching the Intranet. Relationships among investigated variables were significantly different between groups with a high level and a low level of voluntariness. The impact of the Intranet usage on the performance was greater in the higher level voluntariness group than in the lower one. For the lower level voluntariness group, the user's IT usage had the highest effect on the Intranet usage among the three antecedent variables. In short, our study suggests that the higher the perceived voluntariness is the more IS usage will be. Perceived voluntariness was found to have a moderating effect on the relationships among user IT usage level, task interdependency, IS usage, and perceived performance, supporting all the hypotheses on the moderating effect. Most of all, user IT usage level has the strongest influence on IS usage, indicating that users with superior IT usage are more likely to enjoy a high level of perceived performance.

EFfect of Feed Withdrawal Time on Salmonella Contamination in the Crop, Intestinal Weight, and Blood Parameters of Broilers before Harvesting (절식 시간에 따른 육계의 소낭 내 Salmonella 오염도, 소화관 길이, 혈액 성분, 계육 품질에 미치는 영향)

  • Kim, Hee-Jin;Kang, Hwan-Ku;Hong, Eui-Chul;Kim, Hyun-Soo;Son, Jiseon;You, Are-Sun;Kang, Bo-Seok;Jeon, Jin-Joo
    • Korean Journal of Poultry Science
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    • v.48 no.4
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    • pp.287-295
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    • 2021
  • In this study, we aimed to evaluate the impact of different feed withdrawal periods (2, 3, 4, 5, and 6 h) on Salmonella contamination in the crop, intestinal weight, and blood parameters of broilers before harvesting. A total of 100 broilers (initial live weight 1.906±0.06 kg) were randomly assigned to the same five treatment groups and broilers had access to water but no feed before catching. Feed withdrawal times were 2, 3, 4, 5, and 6 h prior to slaughter. Measurements included live weight, pre-slaughter weight, carcass weight, weight of gastrointestinal tract. In addition, Salmonella and Campylobacter contamination in the crop, serum biochemical profiles, counts of leukocytes, erythrocytes, and platelets, and meat quality were assessed. The results demonstrate that carcass weight, blood corticosterone, meat pH, meat color, and water holding capacity did not differ based on the feed withdrawal time. Carcass yield increased as the withdrawal time increased, but the weights of the crop, proventriculus, jejunum, ileum, and rectum were significantly reduced by 6 h (P<0.05). Salmonella counts were the lowest in the crops subjected to 6 h of feed withdrawal (P<0.05). Shear force was highest in chicken breast meat after 6 h of feed withdrawal (P<0.05). However, when the feed was withdrawn after 6 h, the shear force increased, but it did not affect the sensory characteristics in consumers, and the Salmonella count also decreased and had a reduction effect on contamination during slaughter. These findings can serve as reference data for setting the feed withdrawal time.