• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.9 s.240
• /
• pp.971-978
• /
• 2005

Effects of inlet distorted flow on performance, stall and surge are experimentally investigated for a high-speed centrifugal compressor. Tested results for the distorted inlet flow cases are compared with the result of the undistorted one. The performance of compressor is slightly deteriorated due to the inlet distortion. The inlet distortion does not affect the number of stall cell and the propagation velocity. It also does not change stall inception flow rate. However, as the distortion increases, stall starts at the higher flow rate for low speed and at the lower flow rate for high speed. For 50,000 rpm stall occurrs as the flow rate decreases, however disappears fur the smaller flow rate. This is due to the interaction of surge and stall. After the stall and surge interact, the number of stall cell decreases.

• 한국경영정보학회:학술대회논문집
• /
• 2007.06a
• /
• pp.576-581
• /
• 2007

The purpose of this paper is to strengthen trust on the automated collaborative filtering system. Automated collaborative filtering system is quickly becoming a popular technique for recommendation system. This elaborative methodology contributes for reducing information overload and the result becomes index of users' preference. In addition, it can be applied to various industries in various fields. After it collaborative filtering system was developed, many researches are executed to enhance credibility and to apply in various fields. Among these diverse systems, collaborative filtering system which uses Pearson correlation coefficient is most common in many researches. In this paper, we proposed new process diagram of collaborative filtering algorithm and new factors which should improve the credibility of system. In addition, the effects and relationships are also tested.

• 한국경영정보학회:학술대회논문집
• /
• 2007.06a
• /
• pp.415-420
• /
• 2007

Diffusion of information and communication technologies is a global phenomenon. In spite of rapid globalization there are considerable differences between nations in terms of the adoption and usage of new technologies. Several studies exploring causal factors including national cultures of information and communication technology adoption have been carried out. The focus of this paper is slightly different from other studies in this area. Rather than concentrating on the individual information technology the cyber diplomacy is the focus. This research conducted an analysis of the impact national culture has on adoption of the cyber diplomacy and its components for 95 countries. The national cultural dimensions were identified using Hofstede's model of cultural differences. The research model and hypotheses were formed and tested using correlation and regression analysis. The findings indicate that worldwide cyber diplomacy adoption is related to national culture. The result has theoretical and practical implications.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.4
• /
• pp.64-71
• /
• 2011

Homogeneous charge compression ignition (HCCI) was the best concept able to provide low NOx and PM in diesel engine emissions. This new alternative combustion process was mainly controlled by chemical kinetics in comparison with the conventional combustion in internal combustion engine. In this paper, detailed kinetic reaction mechanisms of diesel surrogate was investigated to understand the diesel HCCI engine combustion. It was tested two existing mechanisms and two new mechanisms for the comparison of experimental result. The best mechanism for diesel surrogate was suggested through this comparison.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.15 no.6
• /
• pp.114-119
• /
• 2007

Because the small trailers do not have the main brake system, it is difficult to gain the effective braking performance of the trailers while driving them. Especially it is very hard to brake them on the slope road condition. So we have technically developed Inertia Braking System for the military trailers which have not main braking system. Inertia Braking System is designed to be activated by the inertia force of trailer. It consists of the brake rod, damping cylinder, hand brake lever and brake cables. We have tested the trailer's braking performance. As a result, we have showed that the trailer's braking performance of the trailer equipped with Inertia Braking System, the road driving performance and the braking safety capability are improved dramatically. And we hope that it is rare to happen the accident while driving.

• Korean journal of food and cookery science
• /
• v.26 no.5
• /
• pp.552-558
• /
• 2010

This study was performed to provide basic data on the use of green laver for jook. To accomplish this, we tested water content, color, brightness, mechanical qualities and sensory qualities in comparison to a control group. Higher concentration of green laver powder decreased water content, lightness, redness, viscosity and pH. Further, higher concentration of green laver resulted in lowered preference regarding appearance. However, better flavor was with the result of a higher amount of green laver. Therefore, green laver seems to have benefits for use in oriental soup. Accordingly, we expect there is potential for use of green laver for jook.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2006.04a
• /
• pp.243-248
• /
• 2006

In this paper, we propose the unsupervised change detection algorithm that apply the similarity measure techniques to the hyperspectral image. The general similarity measures including euclidean distance and spectral angle were compared. The spectral similarity scale algorithm for reducing the problems of those techniques was studied and tested with Hyperion data. The thresholds for detecting the change area were estimated through EM(Expectation-Maximization) algorithm. The experimental result shows that the similarity measure techniques and EM algorithm can be applied effectively for the unsupervised change detection of the hyperspectral data.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.25 no.4
• /
• pp.161-169
• /
• 2017

The Human Factors Analysis and Classification System (HFACS) is a general human error framework originally developed and tested within the U.S. military as a tool for investigating and analyzing the human causes of aviation accidents. Based upon Reason's (1990) model of latent and active failures, HFACS addresses human error at all levels of the system, including the condition of aircrew and organizational factors. As a result, this study aims to examine the influence between the latent conditions based on HFACS. This study seeks to verify the factors of "Organizational Influence" effecting the "Precondition for Unsafe Acts" of HFACS. The results of empirical analysis demonstrated that the organizational influence had a positive influence on precondition for unsafe act, especially the "Organizational Climate" of organizational influence had even greater influence on precondition for unsafe acts.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.1 s.244
• /
• pp.90-96
• /
• 2006

Since Risk Based Inspection(RBI) was introduced to quality the risks for jet engine and nuclear power, the technique has been expanded to the area of petrochemical plant. Recently among USA and Europe, window-based computer programme for RBI has been rapidly developed. When local companies procure such program to apply to their plants, it is difficult to build up a proper database as well as expect a good result. In this regards, K-RBI programme accustomed to Korean environments was developed. After completion of the programme in 2004, it was tested by 2 local petrochemical plants and was produced fruitful results. By using these programme, we are expecting accident prevention through risk based planning and implementing of equipment inspection, and saving dollars caused by procuring foreign expensive programme.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.164-169
• /
• 2005

Microphone array techniques are being used widely in wind tunnel measurements for identification of the distributed aerodynamic noise sources on the model being tested. Depending on the frequencies and sound levels, conventional beamforming algorithm has limitation in separating two adjacent sources. Several modifications to the classical beamforming have been developed to enhance way resolution and reduce sidelobe levels. In this Paper the robust adaptive beamforming and the CLEAN algorithm are used to compare to the result of conventional beamforming method. It is found that the CLEAN algorithm is capable of pin-pointing locations of multiple sources nearby, while these sources are unidentifiable with robust adaptive or conventional beamforming techniques.