• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.649-655
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• 2020

This study determined effective educational strategies by investigating and analyzing the related educational demands for SMEs (small and medium-sized enterprises) in the 4th Industrial Revolution based area of smart farms. In order to derive the approprate educational strategies, Importance-Performance Analysis (IPA) and Borich's Needs Assessment Model were conducted based on the smart farm technological field. As a result, the education demand survey showed high demand for production systems and intelligent farm machinery. In detail, Borich's analysis showed the need for pest prevention and diagnosis technology (8.03), network and analysis SW linkage technology (7.83), and intelligent farm worker-agricultural power system-electric energy hybrid technology (7.43). In contrast, smart plant factories (4.09), lighting technology for growth control (4.46) and structure construction technology (4.62) showed low demands. Based on this, the IPA portfolio shows that the network and analysis SW linkage technology and the CAN-based complex center are urgently needed. However, the technology that has already been developed, such as smart factory platform development, growth control lighting technology and structure construction technology, was oversized. Based on these results, it is possible to strategically suggest the customized training programs for industrial sectors of SMEs that reflect the needs for efficiently operating smart farms. This study also provides effective ways to operate the relevant training programs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.326-332
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• 2018

Korea faces major changes in energy policy, which include eco-friendly and zero-nuclear power. On the other hand, there are very few policies for the waste-management of mid- to large-sized lithium-ion batteries, such as electric car batteries and energy storage systems, which are expected to increase explosively due to such energy policy changes. Therefore, this study estimated the amount of mid- to large-sized lithium ion batteries waste and performed economics analysis of a middle and large sized secondary battery recycling project. Based on the results, a policy alternative for the revitalization of the related lithium-ion battery recycling industry is suggested. As a result, the B / C ratio of a domestic mid - to large - sized lithium ion battery recycling project is 1.06, in which the benefit is higher than the cost, so the business is economic feasible. Although the recycling project's economic efficiency is high, the recycling industry has not been activated in Korea because the domestic demand for rechargeable batteries recycling is very low. To solve this problem, this study proposes a plan to activate the industry by adding lithium secondary batteries to the EPR (Extended Producer Responsibility) items.

• Journal of the Korean Vacuum Society
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• v.21 no.6
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• pp.312-321
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• 2012

The electric potential of plasma column is measured with the high voltage probe in a pair of atmospheric plasma jets operated by AC-voltage. According to the polarity of voltage applied to the electrodes, the polarity of plasma column potential has the same polarity of applied voltage. The high potential of plasma column at the side of high voltage electrode is decreased linearly along the plasma column to the ground side. Therefore, the plasma column seams to be a kind of resistor whose resistivity is a few 10s $M{\Omega}/m$. In the experiment of double-jets system, the polarity of plasma potential is verified to be the same polarity to the applied voltage. When the different voltage polarities are applied to the electrodes of double plasma jets, the attractive force is acted between two plumes at the merged plasma and the plasma potential is measured to be low as a few 10s V. When the same polarity of voltage is applied to the electrode, the repulsive force is acted and the plasma potential is measured to be high as a several 100s V at the merged plumes. In the exposure of plasma plume on the bio-substrate with the double plasma jets, the electric shock and thermal damage might be proportional to the plasma power which is the multiplication of the plasma potential and the plasma current.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.4
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• pp.247-254
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• 2012

Vitrification technology has been widely applied as one of effective processing methods for wastes generated in nuclear power plants. The advantage of vitrifying for low- and intermediate-level radioactive wastes has a large volume reduction and good durability for the final products. Recently, a filter using on HVAC(Heating Ventilating & Air Conditioning System) is composed with media (glass fiber) and separator (aluminum film) has been studied the proper treatment technology for meeting the waste disposal requirement. Present paper is a feasibility study for the filter vitrification that developing of the glass compositions for filter melting and melting test for physicochemical characteristic evaluation. The aluminum metal of film type is preparing with 0.5 cm size for proper mixing with glass frit, glass fiber is also preparing with 1 cm size within crucible. The glass compositions should be developed considering molten glass are related with wastes reduction. Glass compositions obtained from developing on glass formulation are mainly composed of $SiO_2$ and $B_2O_3$ for aluminum metal. A variety of factors obtained from the glass formulation and melting test are reviewed, which is feeding rate and glass characteristics of final products such as durability for implementing the wastes disposal requirement.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.265-282
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• 2008

Based on the site characterization works in a low and intermediate level waste(LILW) repository site, the numerical simulations for groundwater flow were carried out in order to understand the groundwater flow system of repository site. To accomplish the groundwater flow modeling in the repository site, the discrete fracture network(DFN) model was constructed using the characteristics of fracture zones and background fractures. At result, the total 10 different hydraulic conductivity(K) fields were obtained from DFN model stochastically and K distributions of constructed mesh were inputted into the 10 cases of groundwater flow simulations in FEFLOW. From the total 10 numerical simulation results, the simulated groundwater levels were strongly governed by topography and the groundwater fluxes were governed by locally existed high permeable fracture zones in repository depth. Especially, the groundwater table was predicted to have several tens meters below the groundwater table compared with the undisturbed condition around disposal silo after construction of underground facilities. After closure of disposal facilities, the groundwater level would be almost recovered within 1 year and have a tendency to keep a steady state of groundwater level in 2 year.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1132-1141
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• 1996

Heterogeneous cation exchange membrane(HCEM) was prepared with LLDPE(Linear Low Density Poly-ethylene) as binder, powdered cation exchange resins($diameter{\leq}149{\mu}m$) as ion-exchange material and glycerol as additive for electrodialysis and electrodeionization system. The weight ratio of (binder/ion exchange)/glycerol was (60%/40%)/5%, (55%/45%)/5%, (50%/50%)/5% and (40%/60%)/5%. The characterization of prepared HCEM was evaluated on mechanical, electrochemical, morphology and ion permeable properties. It was compared with commercial membrane. Electrochemical properties of HCEM of (50%/50% )/5% were very similar to value of IONPURE(commercial membrane), in which ion exchange capacity, ion transfer number and membrane resistance were to be 1.733meq/g, 0.96 and $16.08{\Omega}/cm^2$, respectively. Ion permeability of the membrane was better than that of IONPURE membrane. Compared with IONPURE membrane, the HCEM had a higher tensile strength and lower elongation and modulus, in which HCEM had tensile strength of $62.33kg/cm^2$, elongation of 87.42% and modulus of $658.53kg/cm^2$. The HCEM of (50%/50% )15% was optimum combination.

• Journal of the Korean Solar Energy Society
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• v.32 no.4
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• pp.24-33
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• 2012

Recently, finishing materials at spandrel area, a part of curtain-wall system, are gradually forced to improve thermal insulation performance in order to enhance the building energy efficiency. Also, Building Integrated Photovoltaics(BIPV) systems have been installed in the exterior side of the spandrel area, which is generally composed of windows. Those BIPVs aim to achieve high building energy efficiency and supply the electricity to building. However, if transparent BIPV module is combined with high insulated spandrel, it would reduce the PV efficiency for two major reasons. First, temperature in the air space, located between window layer and finishing layer of the spandrel area, can significantly increase by solar heat gain, because the space has a few air density relative to other spaces in building. Secondly, PV has a characteristics of decreased Voltage(Voc and Vmp) with the increased temperature on the PV cell. For these reasons, this research analyzed a direct interrelation between PV Cell temperature and electricity generation performance under different insulation conditions in the spandrel area. The different insulation conditions under consideration are 1) high insulated spandrel(HIS) 2) low insulated spandrel(LIS) 3) PV stand alone on the ground(SAG). As a result, in case of 1) HIS, PV temperature was increased and thus electricity generation efficiency was decreased more than other cases. To be specific, each cases' maximum temperature indicated that 1) HIS is $83.8^{\circ}C$, 2) LIS is $74.2^{\circ}C$, and 3) SAG is $66.3^{\circ}C$. Also, each cases yield electricity generation like that 1) HIS is 913.3kWh/kWp, 2) LIS is 942.8kWh/kWp, and 3) SAG is 981.3kWh/kWp. These result showed that it is needed for us to seek to the way how the PV Cell temperature would be decreased.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.245-250
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• 2011

Parallel imaging technique can provide several advantages for a multitude of MRI applications. Especially, in SENSE technique, sensitivity maps were always required in order to determine the reconstruction matrix, therefore, a number of difference approaches using sensitivity information from coils have been demonstrated to improve of image quality. Moreover, many filtering methods were proposed such as adaptive matched filter and nonlinear diffusion technique to optimize the suppression of background noise and to improve of image quality. In this study, we performed SENSE reconstruction using computer simulations to confirm the most suitable method for the feasibility of filtering effect and according to changing order of polynomial fit that were applied on variation of spatial resolution of sensitivity map. The image was obtained at 0.32T(Magfinder II, Genpia, Korea) MRI system using spin-echo pulse sequence(TR/TE = 500/20 ms, FOV = 300 mm, matrix = $128{\times}128$, thickness = 8 mm). For the simulation, obtained image was multiplied with four linear-array coil sensitivities which were formed of 2D-gaussian distribution and the image was complex white gaussian noise was added. Image processing was separated to apply two methods which were polynomial fitting and filtering according to spatial resolution of sensitivity map and each coil image was subsampled corresponding to reduction factor(r-factor) of 2 and 4. The results were compared to mean value of geomety factor(g-factor) and artifact power(AP) according to r-factor 2 and 4. Our results were represented while changing of spatial resolution of sensitivity map and r-factor, polynomial fit methods were represented the better results compared with general filtering methods. Although our result had limitation of computer simulation study instead of applying to experiment and coil geometric array such as linear, our method may be useful for determination of optimal sensitivity map in a linear coil array.

• Journal of Biomedical Engineering Research
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• v.34 no.1
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• pp.8-13
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• 2013

Persons with sensorineural hearing impairment have troubles in hearing at noisy environments because of their deteriorated hearing levels and low-spectral resolution of the auditory system and therefore, they use hearing aids to compensate weakened hearing abilities. Various algorithms for hearing loss compensation and environmental noise reduction have been implemented in the hearing aid; however, the performance of these algorithms vary in accordance with external sound situations and therefore, it is important to tune the operation of the hearing aid appropriately in accordance with a wide variety of sound situations. In this study, a sound classification algorithm that can be applied to the hearing aid was suggested. The proposed algorithm can classify the different types of speech situations into four categories: 1) speech-only, 2) noise-only, 3) speech-in-noise, and 4) music-only. The proposed classification algorithm consists of two sub-parts: a feature extractor and a speech situation classifier. The former extracts seven characteristic features - short time energy and zero crossing rate in the time domain; spectral centroid, spectral flux and spectral roll-off in the frequency domain; mel frequency cepstral coefficients and power values of mel bands - from the recent input signals of two microphones, and the latter classifies the current speech situation. The experimental results showed that the proposed algorithm could classify the kinds of speech situations with an accuracy of over 94.4%. Based on these results, we believe that the proposed algorithm can be applied to the hearing aid to improve speech intelligibility in noisy environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2857-2863
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• 2014

IR-UWB has been developed as a standard of indoor ranging technology, because it has robust and good transmission characteristics in indoor environments and it can be operated with low power. In this paper, a IR-UWB packet analyzer is designed and implemented based on IEEE 802.15.4a, which is useful in developing IR-UWB real time location system with resolution of a few ten centimeters. A sniffer device of the packet analyzer monitors IR-UWB wireless networks, captures MAC packet frames, and transmits packet frames to the packet analyzing computer. The packet analyzing program in a computer analyzes received MAC packet frames and displays parsed packet information for developing engineers. Developed packet analyzer is used to analyze IEEE 802.15.4a MAC protocol, and also it can be used in other IEEE 802 series MAC protocol by modifying some functions.