• Journal of computational fluids engineering
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• v.20 no.2
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• pp.88-95
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• 2015

Blood pump analysis process includes both mechanical and bio-mechanical aspects. Since a blood pump is a mechanical device, it has to be mechanically efficient. On the other hand, blood pumps function is sensitively related to the blood recirculation; hence, bio-factors such as hemolysis and thrombosis become important. This paper numerically investigates the mechanical and bio-mechanical performances of the Rotaflow in the extracorporeal membrane oxygenation(ECMO), Ventricular Assist Device(VAD), and full-load conditions. The operational conditions are defined as(400[mmHg], 5[L/min.]), (100[mmHg], 3[L/min.]), and (600[mmHg], 10[L/min.]) for ECMO, VAD, and full-load conditions, respectively. The results are presented and analyzed from the mechanical aspect via performance curves, and from bio-mechanical aspect via focusing on hemolytic characteristics. Regions of top and bottom cavities show recirculation in both ECMO and VAD condtions. In addition, Eulerian-based calculation of modified index of hemolysis(MIH) has been investigated. The results demonstrate that the VAD condition has the least risk of hemolysis among the others, while the full-load condition has the highest risk.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.3
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• pp.153-159
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• 2001

A system simulation program was developed for a multi-type inverter heat pump. Electronic expansion valve(EEV) was used to extend the capacity modulating range of the heat pump as expansion device. The program was also developed to calculate actual system performance with the building load variation with climate during a year. The performance variation of a multi-type hat pump with two EEV and an inverter compressor was simulated with compressor speed, capacity, and flow area of the EEV. As a result, the optimum operating frequency of the compressor and openings of the expansion device were decided at a given load. As compressor speed increased, he capacity of heat pump increased, the capacity of heat pump increased. Therefore flow area of EEV should be adjusted to have wide openness. Thus the coefficient of performance(COP) of the heat pump decreased due to increasement of compressor power input. The maximum COP point at a given load was decided according to the compressor speed. And under the given specific compressor speed and the load, the optimum openings point of EEV was also decided. Although the total load of indoor units was constant, the operating frequency increased as the fraction of load in a room increased. Finally ad the compressor power input increased, the coefficient of performance decreased.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.343-351
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• 2008

In this paper, a spiral shaped common mode filter(CMF) embedded in a flexible printed circuit board(FPCB) is proposed for a multi-function cable. The CMF embedded in a FPC cable presents a new concept as a multi-function cable by the common mode rejection characteristics without a surface mounted device(SMD) CMF. The embedded CMF has a wideband common mode rejection bandwidth and an enhanced differential mode characteristics compared to conventional CMFs that use a magnetic material such as a ferrite of high loss. The proposed CMF of 3 turn inductors has a common mode rejection bandwidth from 0.4 GHz to 3.12 GHz and has 1.95 dB at 3 GHz, 6.97 dB at 8 GHz improvements of a differential mode insertion loss compared to the commercial LTCC(Low Temperature Co-fire Ceramics) CMFs.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.255-261
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• 2014

The development of the IT industry brought major changes in modern society. That change applies in all areas, that life is more and more convenient. work is more efficient, handling quickly and that make convenient life. Interface is a big factor in the center of these changes. that is more and more development and there is currently using NUI technology. NUI technology is not necessary that discrete input device. and that use natural behavior like touch, gesture. among them, the smart phone device is a representative of appllying the NUI technology. smart phone as well as NUI technology applies kiosk, big table and that use Various fields, such as culture, defense, and advertising industries. In this research, development multi-touch table based multi-touch meeting system. and proposal efficient system possible improvements about Existing meeting system.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.2
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• pp.76-81
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• 2005

This research approached electrical characteristics of organic light emitting diodes getting into the spotlight by next generation display device. Basic mechanism of OLED's emitting is known as that electron by cathode of lower work function and hole by anode of higher work function are driven and recombine exciton-state being flowed in emitting material layer passing carrier transport layer In order to make many electron-hole pairs, we must manufacture device in multi-layer structure. There are Carrier Injection Layer(CIL), Carrier Transport Layer(CTL) and Emitting Material Layer(EML) in multi-layer structure. It is important that regulate thickness of layer for high luminescence efficiency and set mobility of hole and electron.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.3
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• pp.207-215
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• 2013

This paper is channel assignment and scheduling techniques for efficient wireless AMI network. In AMI system, the multi-channel cluster network to be proposed defines the communication channel between NC (Network Coordinator) and CDA (Clustered Data Aggregator) as the network channel. CDA and OMD(Out Meter display) and communication channel between SMD(Smart Meter Device) are defined as the group channel. AMI network of the multi-channel cluster based in which the network channel and group channel is mixed increases the administration efficiency through the physical/logical consumer channel clustering. The reliability of inspection data through the channel use distinguished between the adjacent cluster is enhanced. In addition, the fast aggregation of data is possible and the size of a metering network is increased through the channel allocation of the multichannel cluster based.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5A
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• pp.348-357
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• 2012

Recently, smartphone, notebook, PC and other supporting wireless LAN device have come into wide use. By increasing user that use wireless LAN device, wireless traffic also increased. If wireless traffic through one AP is increase, it causes throughput decrease. To solve this problem, wireless LAN service provider install more AP where overload occurred. But this is not enough. Because stations can't know AP's load factor, and APs do nothing for load balancing. In this paper, we propose Multi-Interface Access Point(MIAP) to solve this problem. MIAP operate same as multiple APs with multi-interface, and MIAP measure each interface's load periodically. If MIAP detect overloaded interface, MIAP transfer station from overloaded interface to under-loaded interface. We conducted an experiment for verifying existing problem, and we found this problem occurred. We plan an experiment scenario for a comparison between existing AP and MIAP, and excute these experiment. In the result, we show MIAP with load balancing can improve total throughput about 72% and stabilize delay jitter than existing AP.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.522-528
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• 2017

In this paper, we propose a multi-band antenna for wearable devices using metal frame coupling. The proposed antenna has a $45mm{\times}35mm$ antenna using metal frame and a ground dual coupling structure. The proposed multi-band antenna in this paper is optimized for small devices such as wearable devices. By using the metal frame as a part of the antenna, the volume of the antenna is reduced and satisfies under VSWR 3:1 impedance bandwidth of 70 MHz (870 ~ 940 MHz) in low frequency band, 280 MHz (1600 ~ 1880 MHz) and 280 MHz (1900 ~ 2170 MHz) in high frequency band. It also verified the applicability of wearable devices by measuring wireless performance indicators such as TRP/TIS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.627-630
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• 2009

The combination of the marine use various multi sensor surveillance system technology with the development of servo motion control algorithm and gyro sensor in six freedom motion is implemented to analyze the movement response. The stabilization of the motion control is developed and Nano driving Precision Pan-Tilt/Gimbal system is obtained from the security positioning cameras with ultra high speed device is used to carry out the exact behavior of the device. The exact behavior will be used to make a essential equipment. Finally the development of the Nano Driving Multi Sensor, Nano of Surveillance System Driving Precision Pan-Tilt/Gimbal optimal design and production, 3-aix Gyro Sensor based with Servo Motion Control algorithm development, Image trace video software and hardware tracking the development is organized and discuss in details. The development of the equipment and the system integration are fully experimented and verified.

• Computers and Concrete
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• v.16 no.4
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• pp.503-529
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• 2015

Traditionally, multi-story buildings are designed to provide stiffer structural support to withstand lateral earthquake loading. Introducing flexible elements at the base of a structure and providing sufficient damping is an alternative way to mitigate seismic hazards. These features can be achieved with a device known as an isolator. This paper covers the design of base isolators for multi-story buildings in medium-risk seismicity regions and evaluates the structural responses of such isolators. The well-known tower building for police personnel built in Dhaka, Bangladesh by the Public Works Department (PWD) has been used as a case study to justify the viability of incorporating base isolators. The objective of this research was to establish a simplified model of the building that can be effectively used for dynamic analysis, to evaluate the structural status, and to suggest an alternative option to handle the lateral seismic load. A finite element model was incorporated to understand the structural responses. Rubber-steel bearing (RSB) isolators such as Lead rubber bearing (LRB) and high damping rubber bearing (HDRB) were used in the model to insert an isolator link element in the structural base. The nonlinearities of rubber-steel bearings were considered in detail. Linear static, linear dynamic, and nonlinear dynamic analyses were performed for both fixed-based (FB) and base isolated (BI) buildings considering the earthquake accelerograms, histories, and response spectra of the geological sites. Both the time-domain and frequency-domain approaches were used for dynamic solutions. The results indicated that for existing multi-story buildings, RSB diminishes the muscular amount of structural response compared to conventional non-isolated structures. The device also allows for higher horizontal displacement and greater structural flexibility. The suggested isolation technique is able to mitigate the structural hazard under even strong earthquake vulnerability.