• Journal of Biomedical Engineering Research
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• v.43 no.3
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• pp.136-146
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• 2022

In this study, it is intended to provide basic data that can help develop a cardiovascular simulator for performance evaluation of pulse wave detectors by identifying the development status of domestic and overseas cardiovascular simulators. A total of 119 papers were selected by excluding duplicate literature, gray literature, and literature not related to a cardiovascular simulator. Based on the selected literature, the research trend of cardiovascular simulators was analyzed. As a result of analyzing the purpose of the study, most of the simulators were developed to evaluate the hemodynamic properties of artificial hearts and valves. In addition, it was used for simulation evaluation or hemodynamic studies such as pulse wave studies. As a result of analyzing configurations of the simulators, a heart most often consisted of only one left ventricle. For blood vessels, the Windkessel model was most often constructed using chambers and valves. In most studies, blood was reproduced by mixing glycerin and water to reproduce both density and viscosity. In addition, as a result of analysis from the perspective of medical device performance evaluation, simulators for evaluating artificial heart and artificial valves have been studied a lot, whereas simulators for blood pressure, pulse wave, and blood flow devices have been relatively insignificant. Based on the review results, we suggested considerations when developing a simulator for performance evaluations of a pulse wave detector.

• Journal of Internet Computing and Services
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• v.24 no.1
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• pp.1-7
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• 2023

Recently, the technology of device-to-device(D2D) communication has been receiving big attention to improve the system performance since the amount of high quality/large capacity data traffic from smart phones and various devices of Internet of Things increase rapidly in 5G/6G based next generation cellular networks. However, even though the system performance of macro cells increase by reusing the frequency, the performance of macro user equipments(MUEs) decrease because of the strong interference from D2D user equipments(DUEs). Therefore, this paper proposes a dynamic channel management(DCM) scheme for DUEs to guarantee the performance of MUEs as the number of DUEs increases in next generation downlink cellular networks. In the proposed D2D DCM scheme, macro base stations dynamically assign subchannels to DUEs based on the interference information and signal to interference and noise ratio(SINR) of MUEs. Simulation results show that the proposed D2D DCM scheme outperforms other schemes in terms of the mean MUE capacity as the threshold of the SINR of MUEs incareases.

• Journal of Ocean Engineering and Technology
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• v.26 no.3
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• pp.1-5
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• 2012

A complex energy saving device has been developed for middle class vessels. The propulsive performance of the developed device is described through a model test. The pre-swirl stator, which recovers the rotational energy of the propeller slipstream, is a well-known energy saving device for large vessels. The pre-swirl stator for a large vessel is usually cast as a part of the stern frame and has a high cost. The manufacture of a cast stator for an existing vessel is almost impossible. The complex device that was developed can be fitted on astern frame by welding. The model tests show a 4-6% efficiency gain for middle class vessels with the developed appendages compared to those with bare hulls.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.169-172
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• 2005

The performance test result of the Arm Fire Device(Ignition Safety Device) for solid rocket which prevents accidental ignition was described. The results of the closed bomb test and the igniter test of the classical mechanical arm fire device and the advanced electro-mechanical arm fire device were presented, and according to the igniter test result it was realized that the electro-mechanical arm fire device has an advantage in aspect of the action time.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.835-837
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• 2002

The 17" Backlight Unit (BLU) employing twelve EEFLs (External Electrode Fluorescent Lamp) has been developed for LCD-TV The characteristics of the EEFL BLU without dual brightness enhancement film (DBEF) were equivalent to those of CCFL (Cold cathode Fluorescent Lamp) BLU employing eight CCFLs with DBEF. Luminance, power consumption and uniformity were 12,000nits, 32watt and 80%, respectively. The inverter of EEFL Backlight Unit is composed of 2 transformers and driven by the sinusoidal waveform.

• Journal of Biosystems Engineering
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• v.22 no.4
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• pp.401-410
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• 1997

Scattering of seeds is one of the problems in the hill- dropping planters with a roller-type metering device. For crops like rice, corns and beans, the hill-dropping is own better for a high yield than the drill planting. The roller type metering device has been used for the drill planters and has many advantages. However, it has a problem of scattering of seeds when they are placed on rows. In this study a method was developed to design the roller type metering device fir the precision hill-droppings. Design parameters were derived to configure completely the geometries of the roller and brush. The method was applied to the design of the metering device of the rice seeding machines. The field test showed that the metering device designed by the method made a better performance of seed placement than that made by the precvious one. The method also can be applied to the design of metering devices for the precise hill-droppings of other crops.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.3
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• pp.213-224
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• 2010

An optically controlled silicon MESFET (OPFET) was fabricated by diffusion process to enhance the quantum efficiency, which is the most important optoelectronic device performance usually affected by ion implantation process due to large number of process induced defects. The desired impurity distribution profile and the junction depth were obtained solely with diffusion, and etching processes monitored by atomic force microscope, spreading resistance profiling and C-V measurements. With this approach fabrication induced defects are reduced, leading to significantly improved performance. The fabricated OPFET devices showed proper I-V characteristics with desired pinch-off voltage and threshold voltage for normally-on devices. The peak photoresponsivity was obtained at 620 nm wavelength and the extracted external quantum efficiency from the photoresponse plot was found to be approximately 87.9%. This result is evidence of enhancement of device quantum efficiency fabricated by the diffusion process. It also supports the fact that the diffusion process is an extremely suitable process for fabrication of high performance optoelectronic devices. The maximum gain of OPFET at optical modulated signal was obtained at the frequency of 1 MHz with rise time and fall time approximately of 480 nS. The extracted transconductance shows the possible potential of device speed performance improvements for shorter gate length. The results support the use of a diffusion process for fabrication of high performance optoelectronic devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.11
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• pp.717-721
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• 2017

We studied the performance enhancement of organic light-emitting diodes (OLEDs) using 2,3,5,6-fluoro-7,7,8,8-tetracyanoquinodimethane ($F_4-TCNQ$) as the hole-transport layer. To investigate how $F_4-TCNQ$ affects the device performance, we fabricated a reference device in an ITO (170 nm)/TPD(40 nm)/$Alq_3$(60 nm)/LiF(0.5 nm)/Al(100 nm) structure. Several types of test devices were manufactured by either doping the $F_4-TCNQ$ in the TPD layer or forming a separate $F_4-TCNQ$ layer between the ITO anode and TPD layer. N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD), tri(8-hydroxyquinoline) aluminum ($Alq_3$), and $F_4-TCNQ$ layers were formed by thermal evaporation at a pressure of $10_{-6}$ torr. The deposition rate was $1.0-1.5{\AA}/s$ for TPD and $Alq_3$. The LiF was subsequently thermally evaporated at a deposition rate of $0.2{\AA}/s$. The performance of the OLEDs was considered with respect to the turn-on voltage, luminance, and current efficiency. It was found that the use of $F_4-TCNQ$ in OLEDs enhances the performance of the device. In particular, the use of a separate layer of $F_4-TCNQ$ realizes better device performance than other types of OLEDs.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.7
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• pp.565-570
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• 2016

This paper presents the characteristics related to needle insertion of a robotic device for the automated biopsy procedure. The automated biopsy device, a main component of the robotic needle insertion type intervention system, allows performance of the full biopsy procedure, except for anesthesia, without direct handling of a radiologist or a tele-operated control. In this study, the needle length parameters corresponding to various insertion depths and precision for needle insertion of the automated biopsy device, are discussed. There were two combinations of needle length parameters for appropriate needle insertion and motion capture-based measurement was performed; 0.156 mm error for the 90 mm length commanded insertion displacement was measured. The pre-defined goal is a maximum 1 mm error and thus our measured error is within the acceptable range. In the repeatability check, it was also shown that the device can implement a highly accurate insertion.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.126-131
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• 2000

Capability and performance of the pliers type coupling device for connection of sea eel pots to loop of main line and automatic separating system were investigated at sea as first trial of developing automatic operating system for sea eel pot fishing boat. Obtained main results are as follows. 1. Maximum tensile load of the pliers type coupling device when connection with high twist PP dan-line as a loop of main line was 1603 N, higher than when connection with low twist PP twine 1379 N. 2. A retention ratio of sea eel pots from main line by connecting with coupling device was successful 100% with high performance without any loss in the sea. 3. A ratio of automatic disconnection between sea eel pots using coupling device and loop of main line was perfect 100% without any trouble.