This study would analyze a survey conducted with 609 workers to use the results as materials for the settlement of safety culture for the characteristics of the establishment by assessing the status of the workers’ exposure to harmful risks and the impact on safety culture to present the following conclusions. This study has significance in that it found that exposure to harmful/dangerous factors in the establishment and the workers’ experiences of occupational accidents affect their perception of safety culture and that in particular, ‘worker safety priority’ of the safety cultural factors was an important factor, and it is judged that continuous studies are necessary so that the perceptions of safety culture will spread in the establishment.

이 글은 전남지역에서 발굴조사 된 상징 지석묘에 대해 상석의 특징, 입지, 성격 등에 대해 검토한 것이다. 상징 지석묘는 지연집단이나 혈연집단들이 그들의 상징적인 기념물로 축조된 지석묘로 제단 또는 묘표석이라 부르던 것을 포함하는 지석묘의 총칭이다. 외형상 웅장하고 주위 지석묘와는 뚜렷이 차별화된 상석을 가지고 있으면서 석실이 발견되지 않는 지석묘로 보았다. 이러한 지석묘는 기반식 지석묘와 함께 탁자식 지석묘가 있다. 전남지역에서 발굴조사 된 탁자식 지석묘는 상석이 100cm 이하로 얇은 편으로 단독입지보다는 군 집에 포함되어 존재한다. 이러한 탁자식 지석묘는 본래의 기능을 상실한 채 무덤 기능을 하였음을 하 부구조 존재를 통해 확인할 수 있다. 주형지석을 포함한 기반식 지석묘로 제작된 상징 지석묘는 수십 톤에 이르는 거대한 상석이 있는 것이 특징이다. 이러한 상징 지석묘의 상석은 단면형태로 볼 때 방형 또는 타원형에 가까운 것으로 구분된다. 또한, 외형상 두께가 강조된 것, 너비를 강조한 형태, 길이· 너비·두께 모든 요소를 강조한 형태로 분류할 수 있다. 상징 지석묘는 단독으로 있는 것도 있지만 군집 묘역 어느 한쪽에 거리를 두고 떨어져 있거나 묘역 중앙에 위치한다. 지형적으로는 다른 군집보다 상대적으로 위쪽 또는 아래쪽에 위치한다. 군집보다 위쪽에 있을 경우는 상징적 의미, 군집보다 아래쪽에 있을 경우는 묘표석 의미가 좀 더 강하게 부여된 된 것으로 보았다. 단독입지는 구릉 또는 평지에서 주변을 관망하기 좋은 곳에 위치한다. 묘표석 또는 제단적 성격이 강하며, 일부 매장주체부가 확인되는 경우는 가매장 시설일 여지가 있다. 군집 중앙은 지석묘 군집배치가 열상일 때 많이 확인된다. 군집 중앙에는 유력자 또는 상징적 인물을 두고, 이를 중심으로 묘역이 조성되었을 때 가능성을 언급하였다. 독립입지는 열상배치와 군집화된 지석묘에서 볼 수 있다. 다른 지석묘군과 일정 거리를 두고 떨어져 위치하는 특징이 있다. 이러한 지석묘는 묘역 을 상징하며, 의례적 성격이 짙다. 지석묘 군집에서 가장 먼저 축조되며, 혈연집단과 더불어 다른 집 단이 공동으로 묘역을 조성하였을 것으로 보았다.

This study analyzed habitat status of barn swallows within 800 m and changes in potential food resource occurrence for 63 nests (Seocheon 23, Sejong 40) where barn swallows breeding was confirmed in Seocheon and Sejong in 2019 and 2020. As a result of checking habitat compositions of barn swallows in the study area, Sejong showed more varieties of habitat types than Seocheon, showing a larger number of dominant groups. Such large number of dominant groups was found to be an advantageous habitat factor for producing flying insects as potential food resources for barn swallows. As for the production of potential food resources, Seocheon had the highest production in dwelling and stream and Sejong had the highest production in the stream. The production of potential food resources differed in production season by habitat type. This study analyzed compositions of the habitat around the breeding site of swallows. It provides basic data necessary for protecting barn swallow habitats by comparing the production timing and production volume of potential food resources occurring in the habitat.

In this study, we consider the problem of forecasting the number of inbound foreigners visiting Korea. Forecasting tourism demand is an essential decision to plan related facilities and staffs, thus many studies have been carried out, mainly focusing on the number of inbound or outbound tourists. In order to forecast tourism demand, we use a seasonal ARIMA (SARIMA) model, as well as a SARIMAX model which additionally comprises an exogenous variable affecting the dependent variable, i.e., tourism demand. For constructing the forecasting model, we use a search procedure that can be used to determine the values of the orders of the SARIMA and SARIMAX. For the exogenous variable, we introduce factors that could cause the tourism demand reduction, such as the 9/11 attack, the SARS and MERS epidemic, and the deployment of THAAD. In this study, we propose a procedure, called Measuring Impact on Demand (MID), where the impact of each factor on tourism demand is measured and the value of the exogenous variable corresponding to the factor is determined based on the measurement. To show the performance of the proposed forecasting method, an empirical analysis was conducted where the monthly number of foreign visitors in 2019 were forecasted. It was shown that the proposed method can find more accurate forecasts than other benchmarks in terms of the mean absolute percentage error (MAPE).

The plastic waste problem is deepening all over the world. Plastic wastes have serious impacts on our lives as well as environmental pollution. The production and use of plastics increases every year, but once they are produced, they usually roam the earth for hundreds or thousands of years to pollute the environment. Although there is growing interest in plastic issues around the world and environmental regulations are being tightened, but no clear solution has yet been found. This study suggests Environmental degradation index (EDI). EDI can help raise consumers’ attention to plastic wastes. In addition, EDI will contribute to reduce them in the future. As far as we know, this is the first study. We developed EDI for the confectionery packaging. This study defines four factors that may affect the environment of confectionery packaging: greenhouse gas emissions, energy consumption, methane emissions, and packaging space ratio. Then we quantify the value of each element and compute EDI as the sum of the four component values. In order to evaluate the feasibility of EDI proposed in this study, confectionery-packaging materials distributed in Korea were collected and analyzed. First, the types of confectionery are classified into pies, biscuits, and snacks and basic data was collected. Then the values of the four components were calculated using existing research data on the environment. We can use the proposed EDI to determine how much a product packing affects the environment.

이 연구에서는 주요 가로수인 왕벚나무를 대상으로 구례지역의 조기낙엽 현황 진단을 위해 제주도와 낙엽비율 비교연구를 진행하였고, 구례군에서 수행가능한 주요 가로수 관리방법을 두 가지로 구분하여 관리방법별 조기낙엽 지연효과와 피해를 규명하여 최적관리방법을 도출하였다. 구례지역은 기상청 단풍시기와 낙엽시기가 유사한 제주도 지역보다 같은 시기 낙엽비율이 높았고, 약제처리, 약제와 관수처리를 진행했을 때 구멍병이 방제되어 낙엽 시기가 2주 지연되었다. 조기낙엽은 왕벚나무의 생장과 개화에 영향을 미쳤으며, 약제와 관수처리를 진행한 관리방 법에서 생장이 가장 높았고, 2년 뒤 개화량이 가장 높은 것으로 추정되었다. 따라서 왕벚나무 가로수의 조기낙엽을 지연시키기 위해 구멍병 방제가 중요하고, 조기낙엽이 수관의 발달과 개화량에 영향을 미칠 수 있으므로 약제와 관수처리를 함께 처리하는 관리방법을 도입하는 것이 필요할 것으로 생각된다.

In this study, we consider the assembly line balancing (ALB) problem which is known as an very important decision dealing with the optimal design of assembly lines. We consider ALB problems with soft constraints which are expected to be fulfilled, however they are not necessarily to be satisfied always and they are difficult to be presented in exact quantitative forms. In previous studies, most researches have dealt with hard constraints which should be satisfied at all time in ALB problems. In this study, we modify the mixed integer programming model of the problem introduced in the existing study where the problem was first considered. Based on the modified model, we propose a new algorithm using the genetic algorithm (GA). In the algorithm, new features like, a mixed initial population selection method composed of the random selection method and the elite solutions of the simple ALB problem, a fitness evaluation method based on achievement ratio are applied. In addition, we select the genetic operators and parameters which are appropriate for the soft assignment constraints through the preliminary tests. From the results of the computational experiments, it is shown that the proposed algorithm generated the solutions with the high achievement ratio of the soft constraints.

These days, the Composite Slabs with Deep Deck plate was commonly used in domestic construction site, and, the application of the Slim Floor system was increased from the Enlargement and High-rise Building. But, Slim Floor system using the Deep Deck was shown safety problem caused by the deflection and local buckling in construction phase when used to more than 6m. Therefore, for solving the problem, the installation of the shores is essential. This study is realize the long span slab without shores from control the deflection through applied the pre-tensioning elements in CAP deck. In addition, by applying the pre-tensioning member as the tensile member of the CAP Deck slab, the pre-tensioning member for the shores tries to be used as the structural member. Accordingly, to determine the flexural performance of the CAP Deck slab through the pre-tensioning force in tensile member, and, the composite effect of the CAP Deck slab by the experiments.

본 연구의 목적은 전남 동남부지역에 분포해 있는 지석묘 연구를 통해 청동기시대 대표 묘제인 지석묘 사회의 변천과정을 파악해 보고자 함이다. 공간상으로는 여수반도와 여수와 접해있는 순천 연안지역, 광 양지역으로 한정하였으며, 연구진행은 지석묘의 군집·입지를 분석을 통해 규모와 분포에 대한 의미를 부 여하려 하였다. 출토유물의 경우 유물간의 공반관계, 부장위치를 통해 부장의미를 파악하려 하였다. 더불어 절대연대를 기준으로 한 지석묘의 변천과 연대를 파악하려 하였다. 그 결과 전남 동남부지역의 지석묘 사회는 다음과 같이 변천된다고 말할 수 있다. Ⅰ기는 지석묘가 처 음 축조되는 시기로 지석묘 문화 형성기에 해당된다. 지석묘는 단장형의 묘역시설을 하고 있으며, 군집내 중심적 위치에 자리 잡고 있다. 출토유물로는 동검과 마제석검류, 옥류 등 위신제가 많으며, 이 점으로 보 아 인근주변에서 중심적인 역할을 했던 집단으로 판단된다. 더불어 지속적으로 영향력을 행사해 왔다고 말할 수 있다. Ⅱ기는 지석묘가 활발하게 축조되는 시기로 지석묘 문화 성행기에 해당된다. 군집의 경우가 다양해지 며, 묘역시설을 갖춘 지석묘가 다수를 점한다. 묘역시설은 장방형과 원형이 주로 축조되며, 형태는 Ⅰ기에 비해 정교하지 못하다. 출토유물은 마제석검과 석촉류가 많아진다. 지석묘 주변으로 송국리식 주거지가 다수 확인되며, 이는 임시 주거지로 판단된다. Ⅲ기에서 지석묘 문화 쇠퇴기이다. 묘역시설은 그 전까지 나타나지 않은 집장형 지석묘군이 존재한다. 출토유물은 마제석검으로 심부와 병두부의 차이는 크며, 심부와 병부의 차이가 모호한 것들이 대부분이다. 마제석촉의 경우 무경식편평촉이 확인되는데, 전남 동남부지역에서 지석묘가 주된 묘제로서 오랜 기간 사용되었음을 판단할 수 있다.

This paper deals with the production plan for the foaming process, the core part of the refrigerator manufacturing process. In accordance with this change, the refrigerator manufacturing process has also been converted into the mixed-model production system and it is necessary to optimize the production release pattern for the foaming process. The pattern optimization is to create a mixed-model combination which can minimize the number of setup operations and maintain mixed-model production. The existing method is a simple heuristic that depends on the demand priority. Its disadvantages are low mixed-model configuration rate and high setup frequency. Therefore, demand partitioning occurs frequently. In this study, we introduce the tolerance concept and propose a new pattern optimization algorithm based the large neighborhood search (LNS). The proposed algorithm was applied to a refrigerator plant and it was found that mixed-model configuration rate can be improved without demand partitioning.

In order to satisfy various desires of consumers, a company should produce a variety of products and the production lot size should be as small as possible inevitably. Then, it requires frequent setup works for the model changes. Since setup works are usually carried out after stopping the operation of the equipment, we must minimize the time required for setup works. Major companies are continuously shortening the setup time over the technical guidance from the leading companies, such as Toyota and their own improvement activities up until now. But small and medium-sized(S&M) companies rely on skills and experience of individual engineers due to lack of the personnel and budget. In this paper, we propose systematic guidelines for writing the setup operation manual to support S&M companies. Major functions of the guidelines are drawing process charts specialized in the setup operation, separating the external and internal setup operations, and minimizing internal setup operations. By utilizing the guidelines, it is expected that S&M companies can prepare and apply their own setup operation manual with a minimum of manpower and money. Then, they can manage setup works in a more efficient and reduce the setup time and lower the production cost.

Recent increases in the use of Deep Deck, and the study was carried out much of the Deep Deck in the country. Research is the most studies on the behavior of the composite slab after the concrete is cured. However, the large stress is generated in the work load(150kgf/m2) at the time of pouring concrete. The Deep Deck does not satisfy the provisions of deflection during construction when applied to more than 6.0m span. In this study, installed a strand or reinforcing bar at the bottom of the Deep Deck. The pressing force of tension on the strand and rebar was carried out an experiment to produce an upward deflection of the Deep Deck. The loading experiment was carried out and the pressing force the UTM load.

These days, the Composite Slabs with Deep deck plate was commonly used in domestic construction site, and, the application of the Slim Floor system was increased from the Enlargement and High-rise Building. But, Slim Floor system using the deep deck was shown safety problem caused by the deflection and local buckling in construction phase when used to more than 6m. Therefore, for solving the problem, the installation of the shores is essential. This study is realize the long span slab without shores from control the deflection through applied the pre-tensioning elements in cap deck. In addition, by applying the pre-tensioning member as the tensile member of the Cap Deck composite slab, the pre-tensioning member for the shores tries to be used as the structural member. Accordingly, to determine the flexural performance of the Cap deck composite slab through the pre-tensioning force in tensile member, and, the composite effect of the cap deck composite slab by the experiments.

According to a simple survey on the current status of the assembly line design, it was found that trial and error methods on the basis of experiences have been used mainly in domestic manufacturing industries, even though there exist a lot of excellent line balancing studies. It seems that more practical researches should be carried out to develop user-oriented line balancing tools especially for small and medium-sized enterprises. This study presents a design of the line balancing tool which can support the line balancing tasks of nonspecialists. The proposed design tool is composed of three major modules: pre-process, line balancing, and post-process. In particular, pre-process and post-process are newly proposed to increase its ease of use. We applied the proposed design to a test problem and test result showed that our practical method may contribute to enhance the efficiency of production operations management.

In this thesis, we surveyed the current status of production operations management to find how to improve the operations efficiency. From the survey research, we have found that practical software tools should be developed to increase the efficiency of production operations management, especially for small and mediumsized enterprises. Although there exist a lot of excellent line balancing researches, the results of our survey represent that trial and error methods on the basis of experiences have been used mainly used in the domestic manufacturing industry. It seems that more practical researches should be carried out to develop user-oriented line balancing tools. As a part of the development of those tools, this thesis proposed a design of the line balancing tool which can support the line balancing tasks of nonspecialists. The proposed design is composed of three major phases: redundancy check of the precedence diagram, line balancing, and modification of the line balancing results. The first phase is to check the precedence diagram of work elements and remove the redundancy. The redundancy may affect the quality of solutions and computational time. Although it is important to prepare a neat and proper precedence data, it is not easy to develop a tidy precedence diagram for laymen. The first phase automatically removes the overlapped data. The next phase is the line balancing algorithm. The proposed algorithm is based on COMSOAL and can solve minimization of the number of work stations given the target production cycle time and minimization of the production cycle time given the number of work stations. Additionally, our suggested method can accommodate the predetermined location constraints. The third phase is to modify the solution suggested by the second phase. Frequently, users may want to change the result to reflect some constraints which were not easy to be included into the line balancing algorithm. So, a practical line balancing tool should provide mechanisms to modify the solution and they should check the precedence violation while a user tries to change the work station of an element. This research suggested a simple mechanism to check the precedence violation. We applied the proposed design to some test problems and test results showed that it performed successfully. Therefore, our method may contribute to enhance the efficiency of production operations management.

Because of user's apathy and carelessness, it is difficult to keep the public places (such as school practical rooms) clean. In this study, we presented a six sigma project to improve the level of cleanliness of a university laboratory. We applied the DMAIC (define, measure, analyze, improve, and control) procedure which is the general methodology of the six sigma project. In the process of DMAIC, we listened to the VOC, quantified the level of cleanliness as the level of sigma, and performed various activities to improve user's consciousness level. As a result of the project execution, cleanliness satisfaction has been increased about more than three times. It is expected that results of the proposed case study can be applied to other public places. Also, this study showed the academy campus can be used as a good place for the practical six sigma education.

This thesis proposes a new social network simulator, which can be used for the social network analysis (SNA). It is composed of three modules; initialization, network evolution, and output generation. For the network evolution module, we suggest a modifie

The purpose of this thesis is to develop a performance rating training tool for the time and motion study. It is widely recognized that rating training tools based on films were made several decades ago and introduced to Korea. However, to the best of our

The existing study on fiber reinforced of the reinforced concrete columns are mainly used to thermosetting resin for evaluate the seismic performance. as compared with thermoplastic resin, thermosetting resin is the advantage of greater strength and stand in high temperature. but, thermosetting resin has many environmental problems about recycling. In this study, better toughness, recyclability and the advantage of rapid construction than thermosetting resin used to the seismic performance evaluation. The existing unreinforced and Superex reinforced concrete compression test specimens experimented with 4 kinds about reinforced repeat. (unreinforced, 1 layer, 3 layers, 5 layers) The test results appear to be increased the maximum load of 98.37% that 5 layers reinforced repeat when compared to unreinforced