• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.16-21
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• 2017

In this paper, a Small-sized and planer resonator design of Magnetic Resonance - Wireless Power Transfer(MR-WPT) were proposed for practical applications of mobile devices, such as a laptop, a smart-phone and a tablet pc. The proposed MR-WPT system were based on four coil MR-WPT and designed as a transmitter part (Tx) and a receiver part (Rx) both are the same shape with the same loop and resonator. There are four different spiral coil type of resonators with variable of line length, width, gap and turns in $50mm{\times}50mm$ size. The both of top and bottom side of substrate(acrylic; ${\varepsilon}_r=2.56$, tan ${\delta}=0.008$) ere used to generate high inductance and capacitance in limited small volume. Loops were designed on the same plane of resonator to reduce their volume, and there are three different size. The proposed MR-WPT system were fabricated with two acrylic substrate plane of Tx and Rx each, the Rx and Tx loops and resonators were fabricated of copper sheets. There are 12 combinations of 3 loops and 4 resonators, each combination were measured to calculate transfer efficiency and resonance frequency in transfer distance from 1cm to 5cm. The measured results, the highest transfer efficiency was about 70%, and average transfer efficiency was 40%, on the resonance frequency was about 6.78 MHz, which is standard band by A4WP. We proposed small-sized and planer resonator of MR-WPT and showed possibility of mobile applications for small devices.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1234-1268
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• 2004

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2002 and 2003 has been carried out. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment/design. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation in diverse facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat transfer, humidity was also interesting to promote comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing research topics. Well developed CFD technologies were widely applied for analysis and design of various facilities and their systems. (2) Heat transfer characteristics of enhanced finned tube heat exchangers and heat sinks were extensively investigated. Experimental studies on the boiling heat transfer, vortex generators, fluidized bed heat exchangers, and frosting and defrosting characteristics were also conducted. In addition, the numerical simulations on various heat exchangers were performed and reported to show heat transfer characteristics and performance of the heat exchanger. (3) A review of the recent studies shows that the performance analysis of heat pump have been made by various simulations and experiments. Progresses have been made specifically on the multi-type heat pump systems and other heat pump systems in which exhaust energy is utilized. The performance characteristics of heat pipe have been studied numerically and experimentally, which proves the validity of the developed simulation programs. The effect of various factors on the heat pipe performance has also been examined. Studies of the ice storage system have been focused on the operational characteristics of the system and on the basics of thermal storage materials. Researches into the phase change have been carried out steadily. Several papers deal with the cycle analysis of a few thermodynamic systems which are very useful in the field of air-conditioning and refrigeration. (4) Recent studies on refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement when new alternative refrigerants are applied. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and new alternative refrigerants including natural refrigerants. Efficiency of various compressors and performance of new expansion devices are also dealt with for better design of refrigeration/air conditioning system. In addition to the studies related with thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out. It should be noted that the researches on two-phase flow are constantly carried out. (5) A review of the recent studies on absorption refrigeration system indicates that heat and mass transfer enhancement is the key factor in improving the system performance. Various experiments have been carried out and diverse simulation models have been presented. Study on the small scale absorption refrigeration system draws a new attention. Cooling tower was also the research object in the respect of enhancement its efficiency, and performance analysis and optimization was carried out. (6) Based on a review of recent studies on indoor thermal environment and building service systems, it is noticed that research issues have mainly focused on several innovative systems such as personal environmental modules, air-barrier type perimeterless system with UFAC, radiant floor cooling system, etc. New approaches are highlighted for improving indoor environmental conditions and minimizing energy consumption, various activities of building energy management and cost-benefit analysis for economic evaluation.

• Journal of Internet Computing and Services
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• v.16 no.2
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• pp.109-115
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• 2015

The new medical device technologies for bio-signal information and medical information which developed in various forms have been increasing. Information gathering techniques and the increasing of the bio-signal information device are being used as the main information of the medical service in everyday life. Hence, there is increasing in utilization of the various bio-signals, but it has a problem that does not account for security reasons. Furthermore, the medical image information and bio-signal of the patient in medical field is generated by the individual device, that make the situation cannot be managed and integrated. In order to solve that problem, in this paper we integrated the QR code signal associated with the medial image information including the finding of the doctor and the bio-signal information. bio-signal. System implementation environment for medical imaging devices and bio-signal acquisition was configured through bio-signal measurement, smart device and PC. For the ROI extraction of bio-signal and the receiving of image information that transfer from the medical equipment or bio-signal measurement, .NET Framework was used to operate the QR server module on Window Server 2008 operating system. The main function of the QR server module is to parse the DICOM file generated from the medical imaging device and extract the identified ROI information to store and manage in the database. Additionally, EMR, patient health information such as OCS, extracted ROI information needed for basic information and emergency situation is managed by QR code. QR code and ROI management and the bio-signal information file also store and manage depending on the size of receiving the bio-singnal information case with a PID (patient identification) to be used by the bio-signal device. If the receiving of information is not less than the maximum size to be converted into a QR code, the QR code and the URL information can access the bio-signal information through the server. Likewise, .Net Framework is installed to provide the information in the form of the QR code, so the client can check and find the relevant information through PC and android-based smart device. Finally, the existing medical imaging information, bio-signal information and the health information of the patient are integrated over the result of executing the application service in order to provide a medical information service which is suitable in medical field.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.1
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• pp.13-24
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• 1988

This paper is concentrated on the development of oxygen transfer system by U-tube deep shaft in biological fluidised bed process. The depth of the shaft is 32 m, it is composed of downcomer and riser. Not only flow pattern and oxygen transfer in the deep shaft but also oxygen limitation in biofilm and oxygen utilization in biological fluidised bed are investigated. In this investigation, driving force for liquid circulation in the deep shaft is affected by air injection depth and gas hold-up in downcomer. Flow pattern of the deep shaft is revealed to plug flow. When flow velocity in the deep shaft is maintained to 0.52 m/sec, $K_La$ value is peak at 25~30 m depth in riser. The efficiency of dissolved oxygen supply which passed from the deep shaft to biological fluidised bed is estimated to 56~81 % in the organic wastewater treatment using the deep shaft and when dissolved oxygen concentration is 9.2 mg/l and over, limiting factors of flux and substrate within biofilm are organic materials. Terefore, organic loadings could be increase without decreasing of BOD removal efficiency.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.3 s.3
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• pp.93-102
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• 2001

In this study, the characteristics of river bed profile fluctuation are become possible to be used effectively in future estimation of Taehwa river general development plan through analysis and examination according to the effects of sediment protection weir located in the area of the estuary of Taehwa river's main channel using HEC-6 model. The flow conditions needed in analysis of the characteristics of river bed profile fluctuation refer the conditions of flow which secures 95 days in a year, flood flow, and design flood examined in the estimation of Taehwa river maintenance basic plan. First, in analysis result of river bed variation range, there is no significant variation in upstream section from Samho-gyo while there are the more active erosion and sedimentation as the more flow in downstream from Samho-gyo. Next, from the result of the capacity of sediment transfer, it is analyzed that sediment transfer capacity in the area of estuary of Taehwa river has no significant difference in before and after removal of the sediment protection weir when design flood flows while it is estimated that the more flow, the bigger sediment transfer capacity. Therefore, it is thought that the installation of a suitable hydraulic structure at the lowest point of Dong-chun tributary joins from the downstream of Taehwa river can be a good device to reduce the accumulation of sediments at the lowest point of Taehwa river considering the reduction plan of sediment inflow caused by removal of the sediment protection weir.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.243-249
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• 2007

In this paper we introduce a system that assists news reporters to easily edit source video anywhere, and transfer the result from a remote site to the station. Presently reporters are bothered to edit source materials, compress and transfer using several separate tools. Moreover such tools have lots of too complicated features to use only for news production. We have integrated file sending and video editing functions together for seamless workflow. News programs usually need promptness in production. For this reason our system is designed to make it possible the one-stop production of news items outside the TV station. Also the system reflects the demands of field workers, that is, easy usage for the beginner and features for speedy news production. One of the most focused is that the reliability of the system is guaranteed in the process of transfer. To achieve this end, we have implemented several error-resilient schemes for unexpected network errors. Our system consists of remote laptop editing terminals and a newsgathering server. DV-format based editing and analog-to-DV converting device are adopted to capture video from not only lightweight DV camcorders but also old-fashioned ENG cameras into laptop computers. We expect that news reporters and cameramen can take terminals anywhere the Internet is available and both editing and sending will be done on the spot. This will help increase the competitive power of our news production.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.35-43
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• 2014

In this paper, it is about to non-contact wireless power transmission according to various conditions of self induction principle between the two planar coils at a transmission unit and a receiving unit based on the theory of wireless power transmission. The experiments are occurred in order to power transfer of noncontact method from designed wireless circuits in the primely coil and secondary coil, and the applying to Half Bridge Resonant converter transmission unit and receiving unit. and that were able to prepared circumstance to calculate of the output voltage and power source. The main power of the inductive coupling the resonant converter at the transmission unit is converted electrical energy using the solar cell module and artificial light source (halogen lamp) as a replace light and received 24 V power supply from solar power was used a input power source for the wireless power transmission device. Experimental results, to received of power is used to illuminate the lighting and to charge the battery in receiving circuit.And the wireless power transmission efficiency measured at the output side of the transmission unit is obtained about 70% to 89% compared to input power of receiving unit.In addition, efficiency were tested through ID verification method and comparing the phase difference between the voltage when foreign substances interfere with wireless power transmission.

• Journal of Internet Computing and Services
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• v.24 no.6
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• pp.91-98
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• 2023

Recently, according to development of artificial intelligence, a wide range of industry being automatic and optimized. Also we can find out some research of using supervised learning for deteceting defect of railway in domestic rail industry. However, there are structures other than rails on the track, and the fastener is a device that binds the rail to other structures, and periodic inspections are required to prevent safety accidents. In this paper, we present a method of reducing cost for labeling using semi-supervised and transfer model trained on rail fastener data. We use Resnet50 as the backbone network pretrained on ImageNet. At first we randomly take training data from unlabeled data and then labeled that data to train model. After predict unlabeled data by trained model, we adopted a method of adding the data with the highest probability for each class to the training data by a predetermined size. Futhermore, we also conducted some experiments to investigate the influence of the number of initially labeled data. As a result of the experiment, model reaches 92% accuracy which has a performance difference of around 5% compared to supervised learning. This is expected to improve the performance of the classifier by using relatively few labels without additional labeling processes through the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.152-156
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• 2016

Wastewater heat recovery heat pump systems use heated wastewater from public baths or factories as the heat pump's heat source. Generally, this system uses a bare tube evaporator. In the heat transfer process from wastewater to refrigerant, thermal resistance is caused primarily by fouling deposits on the outside surface of tube. Fouling directly increases thermal resistance and decreases heat pump efficiency. Thus, it is desirable to eliminate fouling. In this study, we fabricated a fouling mitigation device using a bubbling fluidized bed with cleaning sponge balls in the wastewater bath. Experimental conditions were as follows: $20^{\circ}C$ cold-water temperature, $40^{\circ}C$ wastewater temperature, 100 L/h cold water flow rate, and $0.161m^2$ heat exchanger surface area. Experimental results showed that the thermal resistance of fouling decreased by 56% with the fluidized bed alone and by 86% with both the fluidized bed and cleaning sponge balls.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.689-697
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• 2020

Hazardous and noxious substances (HNS) may cause maritime incidents during marine transportation, which are liable to lead to a large amount of spillage or discharge into the sea. The damage to the marine environment caused by the HNS spill or discharge is known to be much greater than the damage caused by oil spill. Particularly dangerous is HNS, which is deposited or buried in the seabed, as it can damage the organisms that live on, in, and near the bottom of the sea, the so-called "benthos," forming the benthic ecosystem. Therefore, it is vital that the HNS deposited on the seabed be recovered. In order to do so, procedures and equipment are required for accurate detection, stabilization treatment, and recovery of HNS in subsea sediment. Thus, when developing a mechanical recovery system, the performance requirements should be selected using performance indices, and the conceptual design of the mechanical recovery system should be based on performance requirements decided upon and selected in advance. Therefore, this study was conducted to arrive at a conceptual design for a mechanical recovery system for the recovery of HNS deposited on the seabed. In the design of the system, based on the fundamental scenario, the method of suction foundation with the function of self enclosing was adopted for recovering the HNS sediment in the subsea sediment. The mechanical recovery system comprises the suction foundation, pollution prevention, a pump system, control system, monitoring device, location information device, transfer device, and tanks. This conceptual design is expected to be reflected and used in the basic design of the components and shapes of the mechanical recovery system.