• Transactions of the Korean Society of Automotive Engineers
• /
• v.2 no.4
• /
• pp.112-119
• /
• 1994

This study is investigated into the dynamic effect of the manifold configuration during the gas exchange processes using both simulation and experiment, In theoretical study on the flow analysis, the characteristic method is applied to solve the compressible unsteady flow equation, involving the several steady flow boundary conditions. In order to excute the engine experiment efficiently, a data acquisition system is configured by using A/D converter and PC. Good results which coincided experimental data with simulation output were obtained, and it shows that this simulation method can be applied to obtain the optimal design parameters in the intake and exhaust systems.

• Proceedings of the Korean Information Science Society Conference
• /
• 2006.10d
• /
• pp.50-55
• /
• 2006

저전력 연산능력과 무선통신 기능을 포함한 경량의 센서노드들로 구성된 무선 센서네트워크는 자연 환경의 모니터링에서 군사적인 목적에 이르기까지 다양한 어플리케이션을 창출 할 수 있다. 그러나, 다수의 저가 무선 노드를 배치해야 하는 센서네트워크의 특성상 안정성이 높은 고가의 부품을 사용할 수 없어, 이에 대한 보완 방안에 대한 연구가 활발히 진행 중이다. 특히, 무선 노드들 간의 시간동기화는 가용 무선 대역폭이 적은 무선 센서 네트워크에서 TDMA 스케줄링등의 기술을 구현하기 위한 필수적인 기반기술로서 네트워크 특성을 고려한 새로운 동기화 기법을 요구하고 있다. 본 논문에서는, 무선센서노드의 특성을 파악하고 시간 동기화 수행 시 발생할 수 있는 오차요인을 분석하여, 넓은 지역에 산발적으로 분포되는 무선 센서네트워크의 특성을 보완할 수 있는 새로운 시간동기화 기법을 제안한다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.5 no.6
• /
• pp.1-12
• /
• 1997

In an SI engine, the characteristics of the air flow is important not only for the design of the intake system geometry but also for the accurate measurement of the induction air mass. In this study, an air flow rate measurement using the ultrasonic flow meter and hot wire flow meter was conducted at the upstream of the intake port and the throttle. At the upstream of the intake port, the pulsating flow into the cylinder affected by the pressure wave was detected directly with the flow meters instead of pressure sensors. At the upstream of the throttle, the reverse flow phenomena were showed by comparing the flow pattern measured by the hot wire air flow meter and the ultrasonic air flow meter. The results of this study can be used for the analysis of the tuning effect in the intake manifold and estimation of the error in real time measurement for the air flow rate.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.223-226
• /
• 2000

흡기 럼블 소음의 발생원을 규명하고 흡배기계와 엔진을 포함한 1-D 모사 실험을 통하여 흡기럼블 소음을 저감하기 위한 다기관의 구조를 제안하고 실험을 통하여 확인하였다. 흡기 럼블 소음은 다기통 엔진에서 기통간 흡입 편차 외에도 쓰로틀 바디로부터 각 연소실 흡기 밸브 사이의 거리 편차를 인하여 발생하고 거리 편차를 줄여 제작된 흡기 다기관에서 Half Order 성분이 저감되어 럼블 소음이 저감되었다.

• International Journal of CAD/CAM
• /
• v.7 no.1
• /
• pp.103-112
• /
• 2007

This paper presents a practical approach for surface reconstruction from unoriented point clouds. Instead of estimating local surface orientation, we first generate a set of depth images from the input point clouds, and a coarse mesh is then generated based on them by space carving techniques. The resultant mesh is progressively refined by local mesh refinement and optimization according to surface distance measure. A manifold mesh approximating the input points within an given tolerance is finally obtained. Our approach is easy to implement, but has the ability to outputs high quality meshes in different resolutions. We show that the proposed approach is not sensitive to several types of data disfigurement and is able to reconstruct models robustly from variance input data.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2640-2642
• /
• 2001

In this paper, we designed simple serial distributer for multiport which is imposed the primitive ranking with a periodic time of received multipath data. The received data are transmitted from manifold multi-device system to decoder and on data in the multiplexer which is to transmit to PC is selected from binary counter.

• Industrial Engineering and Management Systems
• /
• v.12 no.2
• /
• pp.161-170
• /
• 2013

Deployment of green transportation in reverse logistics is a key issue for low carbon technologies. To cope with such logistic innovation, this paper proposes a hybrid approach to solve practical vehicle routing problem (VRP) of pickup type that is common when considering the reverse logistics. Noticing that transportation cost depends not only on distance traveled but also on weight loaded, we propose a hierarchical procedure that can design an economically efficient reverse logistics network even when the scale of the problem becomes very large. Since environmental concerns are of growing importance in the reverse logistics field, we need to reveal some prospects that can reduce $CO_2$ emissions from the economically optimized VRP in the same framework. In order to cope with manifold circumstances, the above idea has been deployed by extending the Weber model to the generalized Weber model and to the case with an intermediate destination. Numerical experiments are carried out to validate the effectiveness of the proposed approach and to explore the prospects for future green reverse logistics.

• East Asian Journal of Business Economics (EAJBE)
• /
• v.12 no.2
• /
• pp.29-34
• /
• 2024

Purpose: The primary objective of this study was to examine the influence of economic democratization on economic development from diverse perspectives. Research design, Data methodology: Justification of the qualitative literature methods used in this study is essential, as extensive descriptions, justifications, and explanations of the methods used allow researchers to increase the reliability of their studies for specific or specified audiences. Initially, the concept and principal attributes of economic democratization were scrutinized, followed by an exploration of its manifold effects on economic development. Results: Consequently, this study facilitated a comprehensive comprehension of how economic democratization fosters economic growth and advancement in contemporary society. Additionally, the study deliberated on the constraints and hurdles of economic democratization, proposing policy recommendations for future mitigation. Conclusion: In conclusion, this study is anticipated to furnish foundational data for regional economic development to both academia and policymakers. It achieves this by thoroughly evaluating the impact of economic democratization on economic development and delving into the dynamic interaction between democracy and economic progress.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.4
• /
• pp.23-32
• /
• 2002

Combustion and flame propagation characteristics of the liquid phase LPG injection (LPLI) engine were investigated in a single cylinder optical engine. Lean bum operation is needed to reduce thermal stress of exhaust manifold and engine knock in a heavy duty LPG engine. An LPLI system has advantages on lean operation. Optimized engine design parameters such as swirl, injection timing and piston geometry can improve lean bum performance with LPLI system. In this study, the effects of piston geometry along with injection timing and swirl ratio on flame propagation characteristics were investigated. A series of bottom-view flame images were taken from direct visualization using an W intensified high-speed CCD camera. Concepts of flame area speed, In addition to flame propagation patterns and thermodynamic heat release analysis, was introduced to analyze the flame propagation characteristics. The results show the correlation between the flame propagation characteristics, which is related to engine performance of lean region, and engine design parameters such as swirl ratio, piston geometry and injection timing. Stronger swirl resulted in foster flame propagation under open valve injection. The flame speed was significantly affected by injection timing under open valve injection conditions; supposedly due to the charge stratification. Piston geometry affected flame propagation through squish effects.

• Journal of the Korean housing association
• /
• v.28 no.1
• /
• pp.1-8
• /
• 2017

Korea is experiencing unprecedented destruction of communities and crisis of mental health represented by top suicide rate among OECD countries. Its causes are manifold of various factors. One of them is lack of social support and broken communities that are closely related to social capital that is linked to other health indicators such as mortality rates. This studies looks for ways to improve social capital through spatial structure and features especially social capital related to neighborhood. Researchers conducted research literature review and observation on physical features of neighborhood streets and alleys. Review of studies show housing types can affect social capital level. High-rise apartments are related with lower neighborhood related social capital compared to single homes and low-rise multi-housing. Studies that mainly examined the physical features such as street layout showed that social encounters happened around local stores and crossings of small roads. Researchers identified actual streets that are more likely to be related with social activities in the neighborhood. Those streets were with physical elements that helped social exchange such as narrower streets, exposed stairs, street furniture of residents, parks, crossing of streets while other streets were with wider and easier access of cars.