• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.229-234
• /
• 2001

A practical and effective semi-active on-off control law is developed for vibration attenuation of a natural, multi-degree-of-freedom suspension system, when its operational response mode is available. It does not need the accurate system parameters and dynamics of semi-active actuator. It reduces the total vibratory energy of the system including the work done by external disturbances and the maximum energy dissipation direction of the semi-active control device is tuned to the operational response mode of the structure. The effectiveness of the control law is illustrated with a three degree-of-freedom excavator cabin model.

• 인지과학
• /
• 제23권1호
• /
• pp.25-46
• /
• 2012

우리는 단조로운 과제를 할 때 종종 그만두고 싶은 충동을 느낀다. 이러한 중단 충동은 그 일을 얼마나 오래동안 해 왔는지(시간적 요인) 또는 수행하는 과제의 특정요소(사건 기반 요인)에 따라 달라진다. 이 연구에서는 스트룹 과제와 작업기억과제를 사용하여 시간적 요인(반복)과 사건 기반 요인(인지적 충돌)의 함수로서의 중단 충동의 변화를 살펴보았다. 최소작업의 법칙을 비롯한 최신 이론과 마찬가지로 기억 과제에서 중단 충동은 어려운 시행 다음에 더욱 큰 것으로 나타난 반면, 스트룹 과제에서는 반응이 비효율적인 시기인 수행의 초기(초심자) 단계에서만 일치 시행보다 불일치 시행 다음에 중단 충동이 더 큰 것으로 나타났다. 이는 인지적 갈등에 대한 회피반응임을 입증하는 결과이다. 시간적 측면에서 보면 중단 충동은 초기 단계보다 후기 단계에서 더 컸다. 이러한 연구 결과는 만족 지연에 관여하는 비교적 강렬한 동기적 노력의 본질을 명확하게 설명하고 있다.

• 한국전산구조공학회논문집
• /
• 제36권1호
• /
• pp.67-74
• /
• 2023

A meshless technique using the geometric conservation least-squares method (GC-LSM) was devised to discretize the governing equation of linear elasticity. Although the finite-element method is widely used for structural analysis, a meshless method was developed because of its advantages in a moving grid system. This work is the preliminary phase for developing a fully meshless-based fluid-structure interaction solver. In this study, Cauchy's momentum equation was discretized in strong form using GC-LSM for the structural domain, and the Newmark beta method was used for time integration. The solver was validated in 1D, 2D, and 3D benchmarking problems. Static and dynamic results were obtained. The results are more accurate than those of analytic solutions.

• Safety and Health at Work
• /
• 제15권2호
• /
• pp.158-163
• /
• 2024

Objectives: The present paper aimed to examine whether an aging workforce is associated with an increase in work-related fatal injuries and to explore the underlying reasons for this potential increase. Material and methods: Aged workers were defined as those who were at least 55 years old. Work-related fatalities were assessed in aged and young workers who were registered with the workers' compensation system in 2021 in the Republic of Korea. Total waged workers, based on raw data from the Local Area Labor Force Survey in 2021, were used as the denominator to estimate the work-related fatality rates. Results: Most work-related fatalities in the aged workers occurred among individuals working in the "construction sector" (58.9%), those with "elementary occupations (unskilled workers)" (46.1%), and those with the employment status of "daily worker" (60.8%). The estimated incidence (0.973/10,000) of work-related fatalities among aged workers was about four times higher than that (0.239/10,000) among younger workers. "Falling," "collision," "struck by an object," and "trip and slip" were more frequent types of work-related fatalities among aged workers relative to young workers. The category of "buildings, structures, and surfaces" was a more frequent cause of work-related fatalities among aged workers than among young workers. Conclusions: Aged workers had a higher incidence of work-related fatalities than young workers. Frequent engagement in precarious employment and jobs, coupled with the greater physical vulnerability of aged workers, were likely causes of their higher level of work-related fatal injuries.

• 대한인간공학회지
• /
• 제22권3호
• /
• pp.13-26
• /
• 2003

The purpose of this study is to investigate the present conditions of the night work and shift work systems in the heavy chemical industrial complexes found in Changwon, Masan, and Chinhae. Korea. We will attempt to define and classify their problems; and to discover further ways to improve their systems. Fifty production factories were carefully selected as the subjects for this study. The shift systems were classified into five categories. The consecutive night shifts were long in almost all cases with 6 days (36 factories) and 7 days (13 factories). It was found that the night work of about] 2 hours continues for a long period in the weekly rotation full-day shift systems and the night-including non-full-day shift systems, and there was no holiday during a shift cycle in the continuous full-day shift systems. The work time in most shift systems was longer than the 44-hours/week permitted by Korean law. Considering the characteristics of these various types of shift systems, the most essential thing to reduce the shift workers' work load may be to shorten their working hours and improve the schedule of shift systems. It is highly recommended as a fundamental solution. to reduce the portal-to-portal hours from 12 to 8 in the night-including non-full-day shift systems and the weekly rotation full-day shift systems, and at least to employ a 4-team 3-shift system in the continuous full-day shift systems. In addition to this, it should from now on be taken as a goal to restructure the types of shift systems by taking such measures as avoiding continuous night work if possible, providing sufficient off-duty intervals both before and after night shift, providing increased opportunities for workers to nap during night work. and increasing the number of holidays.

• Structural Engineering and Mechanics
• /
• 제66권5호
• /
• pp.557-568
• /
• 2018

An investigation is made in the present work on the post-buckling and geometrically nonlinear behaviors of moderately thick perfect and imperfect rectangular plates made-up of functionally graded materials. Spectral collocation approach based on Legendre basis functions is developed to analyze the functionally graded plates while they are subjected to end-shortening strain. The material properties in this study are varied through the thickness according to the simple power law distribution. The fundamental equations for moderately thick rectangular plates are derived using first order shear deformation plate theory and taking into account both geometric nonlinearity and initial geometric imperfections. In the current study, the domain of interest is discretized with Legendre-Gauss-Lobatto nodes. The equilibrium equations will be obtained by discretizing the Von-Karman's equilibrium equations and also boundary conditions with finite Legendre basis functions that are substituted into the displacement fields. Due to effect of geometric nonlinearity, the final set of equilibrium equations is nonlinear and therefore the quadratic extrapolation technique is used to solve them. Since the number of equations in this approach will always be more than the number of unknown coefficients, the least squares technique will be used. Finally, the effects of boundary conditions, initial geometric imperfection and material properties are investigated and discussed to demonstrate the validity and capability of proposed method.

• Smart Structures and Systems
• /
• 제11권6호
• /
• pp.569-587
• /
• 2013

This paper evaluates the closed loop performance of the reaching law based discrete sliding mode controller with multisensor data fusion (MSDF) in real time, by controlling the first two vibrating modes of a piezo actuated structure. The vibration is measured using two homogeneous piezo sensors. The states estimated from sensors output are fused. Four fusion algorithms are considered, whose output is used to control the structural vibration. The controller is designed using a model identified through linear Recursive Least Square (RLS) method, based on ARX model. Improved vibration suppression is achieved with fused data as compared to single sensor. The experimental evaluation of the closed loop performance of sliding mode controller with data fusion applied to piezo actuated structure is the contribution in this work.

• 무역상무연구
• /
• 제33권
• /
• pp.191-219
• /
• 2007

Section 39(5) of Marine Insurance Act 1906 concerns the case where with the privity of the assured, the ship is sent to sea in an unseaworthy state. The underwriters argue that the assured had"blind-eye knowledge" of the particular respect in which the ship was unseaworthy. Blind-eye knowledge requires a conscious reason for blinding the eye. There must be at least a suspicion of a truth about which one do not want to know and which one refuse to investigate. What has caused greater difficulty is the broad provision in s.17 which appears to be unlimited in its scope. The expression "utmost good faith" appears to derive from the idea of uberrimae fidei, words which indeed appear in the sidenote. The concept of uberrima fides does not appear to have derived from civil law and it has been regarded as unnecessary in civilian systems. S.17 raises many questions. But only two of them are critical to the decision of the present appeal-the fraudulent claim question and the litigation question. It is however necessary to discuss them in the context of a consideration of the problematic character of s.17. In the Star Sea Case, for the defendants to succeed in their defence under this part of the case the defendants have to show that claim was made fraudulently. They have failed to obtain a finding of fraud. It is not enough that until part of the way through the trial the owners failed to disclose to the defendants would have wished to see in order to provide them with some, albeit inadequate, evidential support for their alleged defence under s.39(5). The defence under s.17 fails. The Purpose of this work is to analyze the Star Sea Case, and to explore problems of the MIA relating to the judgement of this case.

• 한국인공지능학회지
• /
• 제7권2호
• /
• pp.1-8
• /
• 2019

This paper, we argue that sector in terms of the creative industries the need to the institutional settle of the rent-a-driver business; the industry could create more than 200,000 jobs, the effect is to bring out the about 4 trillion underground economy and Can be interpreted industry, which contributes to reduce social costs, ranging from 1.7 trillion won to 5.7 trillion per year. Through institutionalization of policy should support. Observation and in-depth interviews were conducted with the law and the president of the rent-a-driver business company. The operating system should be improved. the rent-a-driver business, for the formulation of the work ethic and education is desperately needed. The effect socio-economic contribution effect of the rent-a-driver business industry can be summarized as follows. First, it is an industry that has an operating system utilizing state-of-the-art technology and equipment, and the convergence of creative industries to comply with the market. Second, the effect appears as an industry that creates jobs for the populace to replace the social security system, social safety net is considered as an industry. Third, this is an industry that can be self-reliant in the short term at least political support, the industry is considered in the industry to maximize the effectiveness and efficiency of the support policy.

• 한국응급구조학회지
• /
• 제18권2호
• /
• pp.137-145
• /
• 2014

Purpose: The emergency medical service (EMS) system in Japan is similar to that in Korea. This study reviewed the development of paramedics who are major personnel in the respective EMS system of their country. Methods: We searched law for paramedics and publications in J-stage, MEDLINE and the webpage of Japan's Fire and Disaster Management Agency. Results: Paramedic training had started in Japan in 1991, and most paramedics were employed in fire departments. In Japan, ambulances belonging to fire department are staffed by a three-person unit, including at least one paramedic. Medical control advisory boards were established in all Japanese prefectures in 2003 with the purpose of upgrading the activities of ambulance personnel, including paramedics. The scope of paramedics' work has been widened owing to the continued efforts of medical control advisory boards. This allows them to perform invasive procedures including tracheal intubation, intravenous line placement, and epinephrine administration under medical control of a physician. Conclusion: As paramedics' responsibilities expand, further development of the paramedic role and an effective medical control advisory board system are imperative both Korea and Japan.