• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.869-874
• /
• 2002

Hermetic rotary compressor is one of the most important components for air conditioning system since it has a great effect on both the performance and the noise and vibration of the system. Noise and vibration of rotary compressor is occurred due to gas pulsation during compression process and unbalanced dynamic force. In order to reduce noise and vibration, It is necessary to identify sources of noise and vibration and effectively control them. Many approaches have been tried to identify noise sources of compressor. However, compressor noise source identification has proven to be difficult since the characteristics of compressor noise are complicated due to the interaction of the compressor parts and gas pulsation. In this work, Statistical Energy Analysis has been used to trace the energy flow in the compressor and identify transmission paths from the noise source to the sound field.

• The Journal of Korea Robotics Society
• /
• v.10 no.3
• /
• pp.171-177
• /
• 2015

A telerobot offers a more engaging and enjoyable interaction with people at a distance by communicating via audio, video, expressive gestures, body pose and proxemics. To provide its potential benefits at a reasonable cost, this paper presents a telepresence robot system for video communication which can deliver speaker's head motion through its display stanchion. Head gestures such as nodding and head-shaking can give crucial information during conversation. We also can assume a speaker's eye-gaze, which is known as one of the key non-verbal signals for interaction, from his/her head pose. In order to develop an efficient head tracking method, a 3D cylinder-like head model is employed and the Harris corner detector is combined with the Lucas-Kanade optical flow that is known to be suitable for extracting 3D motion information of the model. Especially, a skin color-based face detection algorithm is proposed to achieve robust performance upon variant directions while maintaining reasonable computational cost. The performance of the proposed head tracking algorithm is verified through the experiments using BU's standard data sets. A design of robot platform is also described as well as the design of supporting systems such as video transmission and robot control interfaces.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.2
• /
• pp.89-95
• /
• 2003

Propulsion system of the current developing satellite is roughly composed of propellant tank and four major modules. Each module prevides the pulse momentum for spacecraft attitude control, filling/draining of propellant and pressurant, propellant filtering, and the change of flow passage in the spacecraft emergency situation, respectively. These modules will be fixed on the propulsion platform with their suitable mounting brackers, so the brackets shall be designed sufficiently to support a function of the modules under launch environment and on-orbit condition. The purpose of this article is to check if all the bracket designs satisfy the defined structural requirements through finite element analysis, and then to verify structural safety.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.3 no.4
• /
• pp.51-57
• /
• 1999

Temperature and velocity controlling of air at inlet position of Ramjet combustor is important under Ramjet engine grounding-test condition since temperature of inlet air increases due to compression process by supersonic flow at inlet position of Ramjet combustor. In this study, Vitiated Air Heater methodology was used to control temperature of air that is inducted into Ramjet combustor. Temperature and velocity of air at Vitiated air heater exit, which is inducted into Ramjet combustor, were measured to evaluate Vitiated air heater system developed in this study. It is shown that temperature and velocity of inducted air can be well controlled using Vitiated air heater system developed in this study, and we could make a Vitiated Air which is almost same with real air.

• The Korea Journal of Herbology
• /
• v.27 no.4
• /
• pp.17-23
• /
• 2012

Objectives : Schisandrae Fructus (SF) has traditionally been used to balance level of body fluid and to strengthen kidney function. It has been reported that the SF extract has antioxidant, hepatoprotective, neuroprotective and anticancer effects. This study investigated an antiproliferative effect of SF extract on PC-3 human prostate cancer cells and analyzed active ingredients of SF extract qualitatively and quantitatively. Methods : We examined the antiproliferative effect of SF extract with MTT assay, DAPI staining and annexin-V/7-AAD double staining. The active ingredients of SF extract were identified by using HPTLC and HPLC/DAD system. Results : SF-chloroform fraction inhibited growth of PC-3 cells and changed the morphology of nucleus in a dose dependent manner. A dose-dependent apoptotic cell death was also measured by flow cytometry analysis. It was analyzed that SF-chloroform fraction contained more schizandrin than other fractions by using HPTLC and HPLC/DAD system. Conclusions : These results suggest that SF extract and schizandrin may be a potential chemotherapeutic agent for the control of PC-3 human prostate cancer cells.

• Transactions of the Korean hydrogen and new energy society
• /
• v.20 no.5
• /
• pp.410-415
• /
• 2009

A hydrogen cooling method is used in a power generator for removing the unnecessary heat due to the windage loss of a rotor and the joule heat of a stator. A MEA (Membrane Electrolyte Assembly) hydrogen generator has been developed and applied as a hydrogen supplying system for the cooling of a 350MW power generator. As a field application result, the average potential of eleven cells and the voltage efficiency were measured 2.26V/cell and 65.4% (Higher Heating Value) respectively at the hydrogen pressure of 6 Bar, the hydrogen flow rate of 9.1L/min, and the current of 150A.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.25 no.1
• /
• pp.78-86
• /
• 2001

The Gasoline Direct Injection(GDI) system has been highlighted due to the improvement of fuel consumption and the control of exhaust emission from gasoline engines. The GDI system includes a high injection pressure, smaller mean diameter, good spray characteristics and stability. We were interested in the development for gasoline direct swirl injector(GDSI) in which the swirler is specially designed with an incident angle. Nymerical analysis was utilized to investigate the internal flow of GDSI with a goal to determine the swirl incident angle and needle lift. Accordingly, it describes characteristics of a GDSI in which the flowrate and spray characteristics are satisfied. especially the spray tip penetration decreases, compared with other type GDI, mean diameter of droplets is from 20${\mu}{\textrm}{m}$ to 25${\mu}{\textrm}{m}$ and spray angle ranges from 64$^{\circ}$to 66$^{\circ}$.

• Journal of KSNVE
• /
• v.9 no.1
• /
• pp.184-188
• /
• 1999

Noise regulation of heavy construction machinery is getting stricter： 3 dB per every 4 year in European community. To meet this requirement many engineers have adopted the enclosing structures with thick absorbing materials and small opening, This increases internal temperature of the enclosure which have engine systems such as electric equipment that are vulnerable to heat, and engine block and muffler that can be regarded as heat sources. So noise control engineers have to consider a coupling problem: combining heat balance and noise reduction. This paper describes this approach by introducing simple heat transfer theory and SEA. The enclosing system of the loader whose enclosing structure consists of two rooms is investigated to show the validity of this method. The results represent that the simple heat transfer theory can be useful to estimate cooling performance when it is linked together by the back pressure theory in duct system. and the radiated noise can also be estimated by the SEA. Therefore a designer can use these approaches to define the opening ratio of an enclosure and the mass flow rate of air considering radiating noise.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.4 s.97
• /
• pp.437-444
• /
• 2005

This paper presents a robust aeroelastic control methodology of a two dimensional flapped wing system exposed to an incompressible flow field. A robust controller is designed using a linear matrix inequality (LMI) approach for the multiobjective synthesis. The design objectives are to achieve a mix of $H_{\infty}$ performance and H₂ performance satisfying constraints on the closed loop pole locations in the presence of model uncertainties. Numerical examples are presented to demonstrate the effectiveness of LMI approach in damping out the aeroelastic response of 3-DOF flapped wing system.

• Journal of the Korea Computer Industry Society
• /
• v.7 no.3
• /
• pp.145-154
• /
• 2006

This paper improves algorithms of Speculative Partial Redundancy Elimination(SPRE) proposed by Knoop et al. Improving SPRE algorithm performs the execution speed optimization based on the information of the execution frequency from profiling and the memory space optimization. The first purpose of presented algorithm is to reduce in space requirements and the second purpose is to de crease the execution time. Since too much weight on execution speed optimization may cause the explosion of the memory space, it is important to consider the size of memory. This fact can be a big advantage in the embedded system which concerns the required memory size more than the execution speed In this paper we implemented the min-cut algorithm, and this algorithm used the control flow graph is constructed with network and partitioned.