• Transactions of the KSME C: Technology and Education
• /
• v.2 no.1
• /
• pp.57-63
• /
• 2014

In this paper new air-cooling system utilizing Stirling engine was proposed for improving efficiency in solar photovoltaic power generation. The solar cell plate was equipped with semi-circular channel for air flow on the backside. Beta-type Stirling engine was installed on the plate and its flywheel was connected to a motor fan by a transmission belt. A forced convective air flow for heat radiation was generated by the operation of the self-starting Stirling engine. The performance tests for power generation of solar cell with or without the proposed air-cooling system were conducted under halogen lamp. From the experimental results, it was found that decline in output voltage of the solar cell with proposed cooling system was 25% less than that of the solar cell without cooling system.

• Journal of Life Science
• /
• v.11 no.2
• /
• pp.126-132
• /
• 2001

Effect of Quartz porphyty(QP) on functional and morphological changes of the liver and kidney was studied in male common finch and white java sparrow fed with the basal diet(Control group) or experimental diet containing 3.0% QP(QP group) for 14 days. There was not significantly different morphological change of the liver upon light microscopic examination in common finch and white java sparrow between control group and QP group. Morphological change of renal tissue upon light microscopic examination in common finch and white java sparrow was not also significantly different between control group and QP group. The concentrations of serum creatinine, blood urea nitrogen, and nric acid as renal functional parameters of common finch and white java sparrow were not significantly different in the both groups. The activity of glutamic oxaloacetic transaminase(GOT) as hepatic functional parameter in common finch was significantly higher in the QP group($\rho$<0.05), whereas the activity of glutamic pyruvic transaminase(GPT) as hepatic functional parameter in common finch was not significantly different in the both groups. The activities of GOP and GPT in white java sparrow were not significantly different in the both groups. The morphologic findings and functional parameters of the liver and kidney observed in common finch and white java sparrow fed with 3.0% QP diet showed evidence of slightly liver damage accompanied with increased release of enzyme and fatty change of the hepatocytes in common finch, suggested that the tissues in some animals can be damaged by feeding a diet supplemented with 3.0% QP.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.10
• /
• pp.3-12
• /
• 2013

Wireless Sensor Network (WSN) is used in the railway field in terms of efficient management and maintenance. Sensor communication technology based on IEEE 802.15.4/ZigBee is used in low speed train. However, it is difficult to apply in the high speed train that exposed to severe wireless channel environments. In this paper, we propose the sensor communication algorithm for high speed train environment. we improve error rate and throughput using Equalizer, Multiple Input Multiple Output (MIMO), Flexible Spreading Factor (SF) and Modulation. Also, we have analyzed the performance of the IEEE 802.15.4/ZigBee based on the standard of physical layer of 2.4GHz band in each algorithms. Simulation results show that proposed algorithms can improve error rate and throughput of conventional system.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.8
• /
• pp.39-44
• /
• 2013

Long Term Evolution (LTE) - Advanced has developed Heterogeneous Network (HetNet) that consists of a mix of macrocells and low-power nodes such as picocells to improve the system performance. Also, to encourage data offloading in HetNet, Cell Range Expansion (CRE) have been introduced. In this paper, we propose a cell selection scheme based on Signal to Interference plus Noise Ratio (SINR) for optimal offloading effect. And we manage the interference for user located in cell range expanded region using Almost Blank Subframe (ABS) with flexible ABS ratio to improve the spectrum efficiency in time domain. Simulation results show that proposed scheme can improve spectrum efficiency of macrocell and picocell user. Eventually, proposed scheme can imporve overall user performance.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.6
• /
• pp.22-32
• /
• 2013

Wireless Sensor Network(WSN) has attracted great interest recently and the necessity of ZigBee has appeared to standardize and apply the upper layer specification based on the IEEE 802.15.4 standard specification in industrial field. Currently, there are many studies about the IEEE 802.15.4/ZigBee communication channel. And it is subject of interest to analyze the performance in various channel environments. In this paper, we propose channel models through the analysis of the IEEE 802.15.4 radio wave propagation characteristics in various channel environments. Also, we have analyzed the performance of the IEEE 802.15.4/ZigBee for the standard of physical layer of 2.4GHz band in each channel environments.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.8
• /
• pp.101-112
• /
• 1999

In this paper, the codebook design method of VQ (vector quantization) is proposed an method to extract feature data of image for multimedia information searching. Conventional VQ codebook design methods are unsuitable to extract the feature data of images because they have too much computation time, memory for vector decoding and blocking effects like DCT (discrete cosine transform). The proposed design method is consists of the feature extraction by WT (wavelet transform) and the data group divide method by PCA (principal component analysis). WT is introduced to remove the blocking effect of an image with high compressing ratio. Computer simulations show that the proposed method has the better performance in processing speed than the VQ design method using SOM (self-organizing map).

• Clean Technology
• /
• v.13 no.4
• /
• pp.257-265
• /
• 2007

As a basic study for the development of pilot-scale distillation process of waste photoresist strippers from semiconductor industry, lab-scale experiments for the recovery of NMP (N-methy1-pyrrolidione) and BDG (Butyldiglycol) from waste photoresist strippers have been made using a spinning band vacuum distillation column. Purities of NMP and BDG obtained from the present experiments were higher than 99.5%. Furthermore, water content was less than 1000 ppm, color grade(APHA) less than 50, most metal contents except sodium less than 1 ppb. Those results indicate that NMP and BDG reclamed by distillation satisfy the their specifications required for the formulation of new photoresist strippers. Recovery rate of NMP and BDG was 96 and 53%, respectively, for type A, and 93 and 57%, respectively, for type B waste PR stripper solution.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.1
• /
• pp.7-15
• /
• 2017

This paper presents the results of the parametric study to investigate the effects of several analysis modeling parameters such as support conditions, member connectivities and cable member stiffness on the main mode shapes and natural frequencies of a representative disaster resilient greenhouse structure. In addition, an ambient vibration test was performed on the representative greenhouse structure and its main mode shapes and natural frequencies were obtained. By comparing the experimental and analysis results, a proper analysis modeling method of the representative greenhouse structure was proposed.

• Journal of Digital Contents Society
• /
• v.13 no.3
• /
• pp.343-352
• /
• 2012

In this paper, we implemented a touchless interface for DID(Digital Information Display) system using gesture recognition technique which includes both hand motion and hand shape recognition. Especially this touchless interface without extra attachments gives user both easier usage and spatial convenience. For hand motion recognition, two hand-motion's parameters such as a slope and a velocity were measured as a direction-based recognition way. And extraction of hand area image utilizing YCbCr color model and several image processing methods were adopted to recognize a hand shape recognition. These recognition methods are combined to generate various commands, such as, next-page, previous-page, screen-up, screen-down and mouse -click in oder to control DID system. Finally, experimental results showed the performance of 93% command recognition rate which is enough to confirm the possible application to commercial products.

• Journal of the Korean Solar Energy Society
• /
• v.34 no.2
• /
• pp.60-65
• /
• 2014

A meteorological(met) tower is the first structure installed during the planning stages of offshore wind farm. The purpose of this paper is to design the met tower with tripod bucket type support structure and to install the sensors. The support structure consist of a central steel shaft connected to three cylindrical steel suction buckets which is more cheaper than monopile or jacket type. And the remote wind condition sensors and marine monitoring equipment, including adcp, pressure type tide gauge, wave height sensors, and scour sensors, remote power supply are installed. The manufactured met tower constructed on sea area which is in front of Gasa island. All of functions of met tower showed normal operation conditions and the wind data got by remote data collection system successfully.