In the present study, numerical analysis algorithm for the hull form optimization was taken into account using optimization algorithm. In this algorithm the sequential quadratic programming method was applied as an optimizer and the potential-based panel method was adopted to get the wave resistance coefficient as the objective function. The hull form was modified using the B-spline surface modeling technique during the whole optimization process. The developed numerical analysis algorithm was applied to a passenger ship and the optimized ship were compared with the original ship.

Emission regulation by Europe and the U.S. on air pollutants from diesel automobiles which include particulate matter and nitrogen oxides are becoming stricter than ever. The SCR uses Urea, which is NH3 diluted by water, and chemically reacts with emission gases reducing over 90% of the NOx created. In this study several problems were observed in a SCR system and Engine control system. Through this analysis we can find out more effective repair factors from the various fault in SCR component.

연안여객선의 사고는 많은 인명의 손실로 이어질 수 있어 그 예방이 무엇보다 중요하다. 2014년 발생한 비극적 세월호 전복사고 이후 이러한 사고가 재발되지 않도록 하기 위해 연안여객선의 안전 확보와 관련한 법제의 개정 및 정비 작업이 진행되어 왔다. 이에는 선박 자체의 감항성 유지를 위한 설비 및 선체와 관련한 규정, 선원의 교육·훈련 등 질적·양적 제고를 위한 규정, 그리고 연안여객선의 안전관리체계의 개선을 위한 규정 등의 개정 및 정비가 포함된다. 이와 관련하여 본 논문은 특히 연안여객선의 안전관리와 관련한 법제의 현황을 분석하여 문제점을 파악하고 개선 방향을 제시하여 연안여객선 안전 확보에 기여하고자 하였다. 이를 통해, 연안여객선 안전관리 법률로서의 해운법의 부적절성, 연안여객선 구분의 부적절성, 선령 연장의 부적절성, 안전관리주체의 혼란성, 그리고 기타 여객선의 개념, 선원의 질적 개선, 과적 방지 및 승객 안전 고지 등에 대해 문제점을 파악하고 그 개선 방향을 제시하였다.

PURPOSES : The Toll Collection System (TCS) operated by the Korea Expressway Corporation provides accurate traffic counts between tollgates within the expressway network under the closed-type toll collection system. However, although origin-destination (OD) matrices for a travel demand model can be constructed using these traffic counts, these matrices cannot be directly applied because it is technically difficult to determine appropriate passenger car equivalent (PCE) values for the vehicle types used in TCS. Therefore, this study was initiated to systematically determine the appropriate PCE values of TCS vehicle types for the travel demand model. METHODS: To search for the appropriate PCE values of TCS vehicle types, a traffic demand model based on TCS-based OD matrices and the expressway network was developed. Using the traffic demand model and a genetic algorithm, the appropriate PCE values were optimized through an approach that minimizes errors between actual link counts and estimated link volumes. RESULTS : As a result of the optimization, the optimal PCE values of TCS vehicle types 1 and 5 were determined to be 1 and 3.7, respectively. Those of TCS vehicle types 2 through 4 are found in the manual for the preliminary feasibility study. CONCLUSIONS: Based on the given vehicle delay functions and network properties (i.e., speeds and capacities), the travel demand model with the optimized PCE values produced a MAPE value of 37.7%, RMSE value of 17124.14, and correlation coefficient of 0.9506. Conclusively, the optimized PCE values were revealed to produce estimates of expressway link volumes sufficiently close to actual link counts.

The tires changes characteristics of the element constituting change. Stiffness is one of the various characteristics of the tire. Stiffness of the tire is change contact contour. it is known to affect vibration and noise of the vehicle. In this study we conduct to find influence of change stiffness of the tire due to vibration characteristics inside passenger car. For this study we choose tires of available on the market and measure vertical spring rate and lateral spring rate. Also through the real passenger car we find vibration characteristics in the inside of car. In conclusion, vibration energy is reducing with increase in the stiffness and we find the high vibration level of low frequency band in passenger car due to decreasing stiffness.

This study is designed to measure the impact of a car’s horse power and torque - aspects related to performance among various factors that affect consumer purchase decision-on consumers when buying a car. The research of the results can be interpreted as indicating that the premise, “The impact of torque and horsepower on consumer purchase decision is not significant,” is true.

오늘날 여행객들의 증가와 함께 이동수단인 운송수단 또한 대형화 추세로 변화하고 있으나, 필요악인 사고 역시 이에 비례해 끊임없이 발생하고 있다. 그런데 주목할 점은 사고 발생 시 희생자의 규모 등 사고피해의 정도가 천차만별이라는 것이다. 전문가들에 따르면, 이는 사고 당시 승무원들이 보여주었던 상황대처 능력이나 리더십에 기인한 바 크다고 한다. 즉 비상상황에서 승객의 안전을 도모하고자 하는 승무원의 리더십이 어떻게 발현되느냐에 따라 승객의 안전이나 희생정도가 크게 달라졌다는 것이다. 본 논문은 이 같은 사실에 착안해 여객선·항공기 승무원의 리더십과 승객안전 간의 상관관계를 논의하고자 한다. 특히 유사시 여객선·항공기 승무원의 리더십 형성에 결정적인 영향을 미치는 것으로 알려진 안전교육을 중심으로 이를 논의하고자 한다. 구체적으로, 본 논문은 여객선과 항공기의 사고사례를 비교분석함으로써 승무원의 안전교육과 그로 인한 리더십의 형성이 유사시 승객안전의 확보에 얼마나 중요한지 실증하고자 한다.

PURPOSES : The purpose of this article is to compare and evaluate the riding comfort of a passenger in tunnels depending on different surface textures of concrete pavement. METHODS: Evaluation of riding comfort is conducted at 17 sections, which have different surface texture such as transverse tinned(TT), longitudinal tinned(LT) and diamond grinded(DG). A triaxial accelerometer was set up on the passenger seat surface of the test vehicle to measure vibrations of an occupant, then the effects of vibration on comfort and health were evaluated by ISO 2631. And microphones were installed at passenger's ears height to measure sound pressure level(SPL) in the test vehicle. Additionally, a surface microphone was installed on the inside of wheel arch to evaluate noise between tire and pavement by NCPX method. All tests were conducted cruising at 100km/h. RESULTS : The results of all tests are as follows. First, both vibration magnitudes for comfort and for health in LT and DG sections are almost same and they represent lower than those in TT sections. Second, the average SPL of DG shows the lowest decibels among them. And third, it is founded that interior noise is significantly affected by noise between tire and pavement. CONCLUSIONS : It may be concluded that DG can provide more excellent riding comfort to passenger than LT or TT. Therefore, it is necessary to consider applying DG to existing pavement surface to improve surface condition when the driving environment especially requires riding comfort like a long tunnel.

In this study, the models before and after improving the support structure of seat motor gear nut are investigated by comparing with vibration analysis. The maximum deformation model 1 becomes higher than model 2. The natural frequency of model 2 becomes higher model 1. The design model to be applied into the safe driving is useful effectively by using the analysis result of the height driving module for automotive power seat.