• 수산해양기술연구
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• 제32권2호
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• pp.164-176
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• 1996

The main intention of this paper is to develop and compare the algorithm based on finite element procedures for nonlinear transient dynamic analysis which has combined effects of material and geometric nonlinearities. Incremental equilibrium equations based on the principle of virtual work are derived by the finite element approach. For the elasto - plastic large deformation analysis of shells and the determination of the displacement-time configuration under time-varying loads, the explicit, implicit and combined explicit-implicit time integration algorithm is adopted. In the time structure is selected and the results are compared with each others. Isoparametric 8-noded quadrilateral curved elements are used for shell structure in the analysis and for geometrically nonlinear elastic behaviour, a total Lagrangian coordinate system was adopted. On the other hands, material nonlinearity is based on elasto-plastic models with Von-Mises yield criteria. Thus, the combined explicit-implicit time integration algorithm is benefit in general case of shell structure, which is the result of this paper.

• 산업경영시스템학회지
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• 제27권4호
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• pp.23-32
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• 2004

This paper addresses a model for the transportation planning that determines the transportation cycle time and the vehicle size to minimize the cost in a distribution system. The vehicle routing to minimize the transportation distance of the vehicles is also determined. A distribution system is consisted of a distribution center and many retailers. Products are transported from distribution center to retailers according to transportation planning. A model is assumed that the time horizon is continuous and infinite, and the demand of retailers is constant and deterministic. Cost factors are the transportation cost and the inventory cost, which the transportation cost is proportional to the transportation distance of vehicle when products are transported from distribution center to retailers, and the inventory cost is proportional to inventory amounts of retailers. A transportation cycle time and a vehicle size are selected among respective finite alternatives. The problem is analyzed, and a illustrative example is shown.

• 벤처창업연구
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• 제12권1호
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• pp.73-85
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• 2017

본 연구는 예비창업자(특성화고, 대학생)들의 기업가정신 및 창업의지를 함양하기 위해, 예비창업자들이 지각하는 진로불확실성과 진로교육이 기업가정신 및 창업의지에 미치는 영향을 검증하는 동시에 진로불확실성과 창업의지(또는 기업가정신)의 관계에서 자기결정성의 매개 효과를 규명하였다. 예비창업자인 특성화고 및 대학생을 대상으로 설문방식으로 자료를 수집하였으며, 최종 381부를 분석에 사용하였다. SPSS Statistics 22를 이용한 실증분석 결과, 첫째, 예비창업자들이 지각하는 진로불확실성과 창업의지는 통계적으로 유의미하지 않았다. 둘째, 예비창업자들이 지각하는 진로불확실성은 기업가정신에 부정적인 영향을 주었다. 셋째, 진로교육은 창업의지에 유의미한 부정적인 영향을 주었다. 넷째, 진로교육은 기업가정신에 유의미한 영향을 주지 않았다. 다섯째, 진로불확실성은 자기결정성에 부정적인 영향을 주었다. 여섯째, 자기결정성은 진로불확실성과 창업의지의 관계를 완전 매개하는 것으로 분석되었다. 마지막으로 자기결정성은 진로불확실성과 기업가정신의 관계를 완전 매개하는 것으로 나타났다. 이러한 결과를 토대로 예비창업자의 창업의지를 향상시키기 위해서는 교육현장에서 진로교육의 범위를 확대 및 강화하여 진로불확실성을 낮추고, 창업자의 자기결정성을 강화하여 내재적 동기부여를 높여야 하겠다. 이때 창업의지와 기업가정신의 고취는 예비창업가의 자기결정성을 높이는 노력과 동시에 진로교육에 창업교육을 포함시키는 제도적 노력 또한 병행되어야 한다.

• 경영정보학연구
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• 제20권1호
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• pp.159-177
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• 2018

정보통신기술의 발전과 함께 인터넷 상에서 유통되는 디지털 정보의 양과 범위가 급격히 증가하고 있다. 주목할 점은 개인정보의 가치가 광범위하게 인식되면서 의도치 않은 유출과 그에 따른 프라이버시 침해와 같은 부작용 역시 빠르게 증가하고 있다는 것이다. 이러한 개인정보 침해로 인한 정보주체의 피해를 구제하기 위해 전세계 각국은 법률적으로 개인정보 자기결정권을 구체화하고 있으나 실제 현장에서 행사되는 경우는 매우 드문 것으로 나타나고 있다. 특히, 일반적 형태의 개인정보에 비해 개인의 신체 및 건강, 진료 등에 대한 민감한 정보를 담고 있는 개인의료정보의 경우, 보안사고 발생 시 더 많은 경제사회적 문제를 가져올 수 있음에도 개인의료정보에 대한 자기결정권 행사는 충분히 이루어지지 못하고 있다. 본 연구에서는 기존 연구에서 보호와 관련된 개인의 의도 및 행동을 설명하기 위한 이론적 프레임워크로 활용되어 온 보호동기이론을 기반으로 개인의료정보의 자기결정권 행사 의도에 영향을 미치는 요인을 살펴보았다. 설문조사를 통해 수집된 200건의 데이터에 대한 실증분석 결과, 위협평가(위협에 대한 지각된 취약성, 지각된 심각성)와 대처평가(지각된 반응 효율성)가 개인의료정보의 자기결정권 행사 의도에 유의한 영향을 미치고 있는 것으로 나타났으며, 개인이 평소 갖고 있는 개인의료정보 제공에 대한 우려 역시 개인의료정보의 자기결정권 행사 의도에 유의한 영향을 주고 있는 것으로 나타났다. 도출된 결과와 관련된 이론적, 실무적 시사점과 본 연구의 한계점 및 향후 연구방향을 제시하였다.

• 한국항해학회지
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• 제18권4호
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• pp.137-146
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• 1994

In this paper, a new algorithm to measure the ultrasonic travel time is proposed, which is fundamental to estimate distance depth and volume in several media. Pulse wave has been used to measure travel time of transmitted signal. However, due to the characteristic of transducer and propagation, the received signal is so distorted that it is difficult to measure travel time, which is propagation, the received signal is so distorted that it is difficult to measure travel time, which is to be time difference between transmitted and received signals. In this proposed method, transmitted and received signal are transformed respectively into norm phase newly designed by this paper and displayed on phase-time curve. And travel time is simply determined by the arithmetic numerical mean of time difference at the identical norm phase on the phase-time curves of transmitted and received signals. This method has several features; firstly, travel time is calculated analytically with high accuracy by least square error method, secondly, it is useful to compare the difference of signal magnitude for time information, thirdly, noise and discrete errors are relatively small, finally, the measurement accuracy is not influenced by D.C. bias. In particular, this method is useful and applicable to measuring very short distance and sound speed with high accuracy.

• Structural Engineering and Mechanics
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• 제82권4호
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• pp.445-458
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• 2022

Some of the control systems used in engineering structures that use sensors and decision systems have some time delay reducing efficiency of the control system or even might make it unstable. In this research, in addition to considering the effect of the time delay in vibration control process, predictive control is used to compensate the time delay. A semi-active vibration control approach with the help of magneto-rheological dampers is implemented. In addition to using fuzzy inference system to determine the appropriate control voltage for MR damper, structural behavior prediction system and specifying future responses are also used such that the time delays occurring within control process are overcome. For this purpose, determination of prediction horizon is conducted for one, five, and ten steps ahead for single degree of freedom structures with periods ranging from 0.1 to 4 seconds, subjected to twenty earthquake excitations. The amount of time delay applied to the control system is 0.1 seconds. The obtained results indicate that for 0.1 second time delay, average prediction error values compared to the case without time delay is 3.47 percent. Having 0.1 second time delay in a semi-active control system reduces its efficiency by 11.46 percent; while after providing the control system with structure behavior prediction, the difference in the results for the control system without time delay is just 1.35 percent on average; indicating a 10.11 percent performance improvement for the control system.

• Journal of Chest Surgery
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• 제14권1호
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• pp.1-8
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• 1981

Alterations in serum enzymes were studied in twenty-five patients who underwent open heart surgery in N.M.C. during the period from June 1979, to Feb. 1980. There were fifteen congenital and ten acquired heart diseases. In all patients, Rygg-Kyvsgaard five head roller pump and Polystan bubble oxygenator were used and serial determination of total level of Creatine phosphokinase [CPK], Lactic dehydrogenase [LDH], Glutamic oxaloacetic transaminase [SGOT] were made preoperatively, operation day [just after aortic clamp release, 2 hrs later, 4 hrs later, 6 hrs later], and postoperative days up to 5th day. Immediate postoperative clinical courses were also evaluated. Twenty-five patients were divided into two groups: Group A[13] was cardiopulmonary bypass time more than 95 minutes and aortic clamp time more than 45 minutes. Group B[12] was cardiopulmonary bypass time less than 95 minutes and aortic clamp time less than 45 minutes. The peak levels of SGOT, LDH in Group A were more significantly elevated than Group B [P<0.05]. But peak levels of CPK were not significant between two groups. In the view of clinical evaluation, poor clinical courses were more frequent in Group A [54%] than Group B[8%].

• 한국농공학회지
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• 제43권2호
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• pp.85-93
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• 2001

The basic concept of the model is to minimize the error range between forecasted flood inflow and actual flood inflow, and forecast accurately the flood discharge some hours in advance depending on the concentration time(Tc) and soil moisture retention storage(Sa). Simplex method that is a multi-level optimization technique was used to search for the determination of the best parameters of RETFLO (REal-Time FLOod forecasting) model. The flood forecasting model developed was applied to several strom event of Yedang reservoir during past 10 years. Model perfomance was very good with relative errors of 10% for comparison of total runoff volume and with one hour delayed peak time.

• 한국동물위생학회지
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• 제15권2호
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• pp.128-133
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• 1992

To obtain the basic data for blood chemistry, the effects of the time elapse of serum separation on bovine blood chemical values were investigated. The results obtained are summerized as follows : 1. The constant fluctuation tendency and significance was not detected in GOT, GPT, BUN, Creatinine, ALP, CPX, Cholesterol, Ca, Mg and Pi. 2. Glucose showed the decrease tendency according to the time elapse of serum separation. As the values at 12 and 24 hours showed significant lower values than those at 1 and 2 hours (p＜0.01) it was thougth that separation time of serum should be focussed for the glucose determination.

• 상하수도학회지
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• 제23권3호
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• pp.279-285
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• 2009

In this study, applied to the industrial water service, it is verified feasibility of break-even analysis method which has not been introduced in Korea. The On-san water pipeline of 7.1km among the Ul-san industrial water service is selected and the optimal replacement time calculated by break-even analysis method is year 2033 to 2044 which will be 53 to 67 years since the pipes were buried. If indirect cost such as the value of lost water and traffic disruption, service interruption, etc. is calculated as 30 and 100% of the direct cost, the financially optimum replacement time is advanced 3 to 9 years. These ways present rational criteria to establish long-term plan for budget and to execute the limited budget efficiently.