High-rise buildings are equipped with TMD (Tuned Mass Damper), a vibration control device that ensure the stability and usability of the building. In this study, the seismic response control performance was evaluated by selecting the design variables of the TMD based on the installation location of the twisted irregular building. To this end, we selected analysis models of 60, 80, and 100 floors with a twist angle of 1 degree per floor, and performed time history analysis by applying historical seismic loads and resonant harmonic loads. The total mass ratio of TMDs was set to 1.0%, and the distributed installation locations of TMDs were selected through mode analysis. The analysis results showed that the top-floor displacement responses of all analysis models increased, but the maximum story drift ratio decreased. In order to secure the seismic response control performance by distributed installation of TMDs in twisted irregular buildings, it is judged that the mass ratio distribution of TMDs will act as a key variable.

Piloti-type structures with vertical irregularity are vulnerable to earthquakes due to the soft structure of the first story. Structural characteristics of buildings can significantly affect the seismic loss function, calculated based on seismic fragility, and therefore need to be considered. This study investigated the effects of the number of stories and core locations on the seismic loss function of piloti-type buildings in Korea. Twelve analytical models were developed considering two variations: three stories (4-story, 5-story, and 6-story) and four core locations (center core, x-eccentric core, y-eccentric core, and xy-eccentric core). The interstory drift ratio and peak floor acceleration were assessed through incremental dynamic analysis using 44 earthquake records, and seismic fragility was derived. Seismic loss functions were calculated and compared using the derived seismic fragility and repair cost ratio of each component. The results indicate that the seismic loss function increases with more stories and when the core is eccentrically located in the piloti-type structure model. Therefore, the uncertainty due to the number of stories and core location should be considered when deriving the seismic loss function of piloti-type structures.

In this study, we investigated the dynamic characteristics of three irregular building models to analyze the effectiveness of displacement response control with Tuned Mass Damper (TMD) installation in twisted irregular buildings. The three irregular models were developed with a fixed angle of twist per story at one degree, subjected to three historical seismic loads and resonant harmonic loads. By designing TMDs with linear and dashpot attributes, we varied the total mass ratio of the installed TMDs from 0.00625% to 1.0%, encompassing a total of 10 values. Two TMDs were installed at the center of the top story of the analysis model in both X and Y directions to evaluate displacement response control performance based on TMD installation. Our findings suggest that the top displacement response control performance was most effective when a 1.0% TMD was installed at the top layer of the analysis model.

선원은 해양관련분야의 핵심 인적자원으로서 해상운송의 중심이었으나, 선원의 가치에 대한 인식저하 등으로 자발적 비정규직이 등장함에 따라 고용안정에 심각한 영향을 미칠 것으로 판단된다. 이에 이 논문은 선원에 대한 직업의식과 법제적 차이를 검토하고 선원의 비정규직화 현상을 개선하기 위하여 선원법령 상 정규직과 비정규직의 차이를 분석하고, 산업계의 실태를 파악하였다. 선원의 공급과 선사의 수요가 같거나 수요가 큰 경우에는 고용형태의 차이 가 없지만 선원의 공급이 선사의 수요보다 큰 경우에는 고용형태에 따른 차이 가 발생할 것으로 판단된다. 선원의 고용형태에 따른 선호도와 인식도 조사를 시행하였다. 고용형태에 대한 정보가 불충분하고 장기승선 기피 등의 이유로 자발적 비정규직은 일정부분 존재할 것이다. 또한 장기승선 기피, 외국인 선원 고용이 한국선원의 일자리 위협요소로 작용함에 따라 정책적인 지원과 선원의 자질향상 및 인권보호, 계층 간 완충역할을 위한 시스템적 접근이 필요할 것이다. 이에 이 논문은 선원의 고용안정화를 위해 일자리 인식도 개선, 직업안정제 도 마련, 퇴직금 중간정산 제한문제에 대한 인식개선 및 선원고용연계를 위한 정책의 필요성을 제안하였다.

본 논문에서는 불규칙 선수파랑 조건에서 선박계류시스템의 전후동요를 억제하는 연구를 수행하였다. 두점식 계류시스템은 비선형복원력의 특성으로 인하여 규칙파 조건에서도 강한 비선형 응답 특성을 보인다. 종방향 불규칙 장파가 외란으로 선박계류시스템에 작용하게 되면 규칙파 외력이 입사하는 경우보다 변위와 속도에서 더욱 복잡한 비선형 거동이 발생한다. 계의 종동요 변위와 속도를 동시에 억제하기 위하여 슬라이딩모드 제어법(SMC)을 적용하였다. SMC는 매개변수의 불확실성 및 외란에 대한 강인성을 갖는 폐루프 시스템을 제공하지만, 채터링은 이 제어법을 사용할 때 큰 단점이 된다. 본 연구에서는 준 슬라이딩모드의 시그모이드 함수를 이용하여 불규칙 해양파의 외란 조건에서 채터링을 줄이고. 수렴의 정확성에 도달하는 목표를 달성하였다. 제어법의 유효성은 수치시뮬레이션을 통해 증명하였다.

With the current increase in national income, consumers are favoring expensive home appliances. Many aluminum parts are used to improve the appearance of TV products. However, many losses are incurred due to production defects. There are many flaws in the bending process. This study studied the improvement of bending defects during fault handling. The material used is an aluminum alloy (6063), and the product is a serrated component on the surface of an aluminum part. After the bending process, it was identified how the sawtooth area was twisted. Then, while bending, experimented to find the main cause of the defect. The study tried to find maximum effectiveness with a minimum experiment using 6 sigma techniques. The experiment showed that there were many defects depending on the bending speed of the part and the distance it was fixed. The experiment used a method of finding optimal conditions by combining variables from each item. As a result, the failure was minimized when the distance between the two axes was maintained at 4.5-5mm and the bending speed was maintained at 15mm/sec. The component fixation force has a fixed hook in the middle of the product, and therefore it is found that changes in the amount of byte for the fixed part do not result in significant improvements in the defect.

In this study, the seismic response is investigated by using a relatively low-rise building under torsion-prone conditions and three seismic loads with change of the location of the seismic isolation system. LRB (Lead Rubber Bearing) was used for the seismic isolator applied to the analytical model. Fixed model without seismic isolation system was set as a basic model and LB models using seismic isolation system were compared. The maximum story drift ratio and the maximum torsional angle were evaluated by using the position of the seismic layer as a variable. It was confirmed that the isolation device is effective for torsional control of planar irregular structures. Also, it was shown that the applicability of the midstory seismic isolation system. Numerical analyses results presented that an isolator installed in the lower layer provided good control performance for the maximum story drift ratio and the maximum torsional angle simultaneously.

Construction of irregular-shaped concrete structures requires a lot of time and money. To reduce the cost and time, the F3D(Free-Form Formwork 3D Printer) technology was adopted in manufacturing EPS(Expanded Polystyrene) formwork for irregular-shaped concrete structure. To design EPS formwork precisely, lateral pressure acting on irregular-shaped formwork and deformation of EPS form liner should be evaluated. However, in current Korean formwork standard, there are no standards for irregular-shaped formwork as it includes a lot of complex variables. For this reason, several researchers developed 3-dimensional finite element analysis model to calculate lateral pressure exerted by fresh concrete. In this study, deformation of irregular-shaped EPS formwork and lateral pressure acting on formwork was examined using finite element analysis model.

Construction techniques and materials are developing and structures are designed to be irregular shaped, and therefore more detailed structural analysis is required. The purpose of this study is to analyze the cause of accidents related to falsework systems during construction and discuss prevention methods in order to prevent accidents relate to prefabricated shoring system during construction. In this paper structural analysis was conducted to study the influence of slab irregularity on system supports and analysis to investigate the participation of the bracing in the system support.

The F3D(Free-Form Formwork 3D Printer) technology that manufactures EPS(Expanded Polystyrene) formworks for irregular-shaped concrete structures by 3D printers was developed to reduce the cost and time. Because of weak strength and low elastic modulus of the EPS, structural performance including lateral pressure by fresh concrete of the formwork that consisted of EPS should be investigated. In order to calculate lateral pressures acting on formwork, several variables including sizes, shapes of formwork, tangential force(fricition) between fresh concrete and formwork, and material properties of fresh concrete should be considered. However, current regulations have not considered the properties of concrete, only focused on vertical formwork. Galleo introduced 3-dimensional finite element analysis models to calculate lateral pressure on formwork. Thus, proposed finite element analysis model based on previous studies were verified for vertical formwork and irregular-shaped formwork. The test results were compared with those by FEM analysis. As a result, the test agrees well with the analysis.

본 연구는 인적자원관행의 보편적 접근법을 토대로 하여 인적자원관행이 기업성과에 미치는 영향과 IMF 이후 비정규직비율이 급격하게 증가하면서 고용불안을 야기하는 현 상황에서 달라진 고용형태, 즉 비정규직 비중이 인적자원관행과 기업성과 간 관계에 미치는 조절효과를 분석하는데 초점을 두고 있다. 분석 결과, 성과배분보상과 고용안정협약은 주관적 재무성과와 유의한 관계를 미치는 것으로 나타났다. 그러나 고용안정협약은 가설과 달리 주관적 재무성과에 부정적 영향을 미치는 것으로 나타났다. 노동생산성에 대해서는 성과배분보상, 직무분석 실시와 종업원 참여가 유의한 정(+)의 영향을 미치는 것으로 나타났다 인적자원관행과 기업성과에 대한 비정규직비율의 조절효과를 실증 분석한 결과, 비정규직 비율 이 높을 경우 공식훈련제도, 직무분석, 종업원 참여와 같은 전략적 인적자원관행의 중요성이 더욱 크다는 것을 알 수 있었다. 즉, 비정규직비율이 높을 경우 종업원에 대한 공식훈련이 더욱 필요하고 직무분석 실 시와 종업원의 경영계획에 대한 의견을 반영하는 노력이 기업성과에 긍정적인 효과를 주는 것으로 확인 되었다. 본 연구는 보편적인 인적자원관행이라고 여겨졌으나 기업을 둘러싸고 있는 여러 상황이 변화함 에 따라 모범사례(best practice)라고 여겼던 일부 인적자원관행이 현 기업 상황에 맞지 않을 수 있다는 점과 비정규직 비율이 높을 경우 보편적인 인적자원관행(human resource practices)의 실시는 더욱 더 중요한 시스템이라는 점을 시사하고 있다. 연구 결과를 토대로 연구의 한계점과 향후 연구방향에 대해 논의하였다.