• Journal of Broadcast Engineering
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• v.22 no.5
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• pp.570-577
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• 2017

Recently, with the development of broadcasting communication, users expect to receive high quality and various broadcasting services anytime, anywhere. In the case of terrestrial broadcasting, HD broadcasting and mobile broadcasting are provided at different frequencies. In the case of terrestrial UHD, which recently started trial broadcasting, 700MHz frequency is used which is different from the existing one. If the contents of the same contents are transmitted at different frequencies, it can be considered ineffective in terms of the use efficiency of the terrestrial broadcast frequency. As a method to solve this problem, a transmission system model and a service have been proposed for transmitting the hierarchical encoded UHD contents by SHVC on the basis of the multimedia transmission technology MMT in a heterogeneous network environment combining broadcast network and communication network. However, it is still in the initial stage of study the receiving model that can reliably receive various quality UHD contents in various environments such as mobile and fixed environment. Therefore, in this paper, we propose a receive buffer model that can reliably receive UHD contents layered on SHVC based on MMT.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.94-104
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• 2008

In this paper, we propose a new architecture of multiplier-and-accumulator (MAC) for high speed multiplication and accumulation arithmetic. By combining multiplication with accumulation and devising a hybrid type of carry save adder (CSA), the performance was improved. Since the accumulator which has the largest delay in MAC was removed and its function was included into CSA, the overall performance becomes to be elevated. The proposed CSA tree uses 1's complement-based radix-2 modified booth algorithm (MBA) and has the modified array for the sign extension in order to increase the bit density of operands. The CSA propagates the carries by the least significant bits of the partial products and generates the least significant bits in advance for decreasing the number of the input bits of the final adder. Also, the proposed MAC accumulates the intermediate results in the type of sum and carry bits not the output of the final adder for improving the performance by optimizing the efficiency of pipeline scheme. The proposed architecture was synthesized with $250{\mu}m,\;180{\mu}m,\;130{\mu}m$ and 90nm standard CMOS library after designing it. We analyzed the results such as hardware resource, delay, and pipeline which are based on the theoretical and experimental estimation. We used Sakurai's alpha power low for the delay modeling. The proposed MAC has the superior properties to the standard design in many ways and its performance is twice as much than the previous research in the similar clock frequency.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.251-258
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• 2016

This article reports current status of micro fuel cell-combined heat and power (${\mu}FC$-CHP) systems which utilize both power and heat generated by fuel cells. There are several options for constructing CHP systems and among them, fuel cells are the most useful and their total energy efficiency combining heat and power can reach up to about 90%. Fuel cells are classified as five types based on the electrolyte, but the most suitable fuel cell types for the ${\mu}FC$-CHP system are proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs). ${\mu}FC$-CHP systems have several advantages such as decrease of the transmission-distribution loss, reduced costs of electricity due to distributed power generation, and environmental-friendliness owing to zero emission. The main drawback of the ${\mu}FC$-CHP systems is the high initial investment, however, it keeps decreasing as the technology development reduces production costs. Currently, Japan is the most leading country of the ${\mu}FC$-CHP market, however, Korea tries to expand the market by planning the deployment of 1 million units of ${\mu}FC$-CHP systems and governmental subsidiary supporting of half of the install price. In this report, integration technologies for connecting FC and CHP, and technology trends of leading countries are presented as well.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.3
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• pp.39-49
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• 2017

Standards suitable for local conditions on deciding one-way road are desperately required to solve traffic congestions at the backside roads in the old downtown areas which were not designated as a road by urban planning. Therefore, this study intends to re-establish a standard to decide one-way road which is regarded to be of the greatest effect among traffic system control methods in order to control one-way road system more efficiently. Also, this paper suggests a standard for such decision to improve efficiency of using backside roads and expand designation of one-way road. AHP (analytic hierarchy process) was carried out among the traffic experts to find out the factors to decide one-way road system. Its result reveals that importance of causing accident to walking quantity and traffic was high. 10,000 cases out of all the possible scenarios of accident by combining detailed evaluation items and scales were extracted to draw the outcomes of analyzing the scenarios, which were schematized in a graph. As a result, division by three sections of point of inflection was verified into $1{\leq}$ section A<1.91, 1.9$1{\leq}$ section B<2.08, and $2.08{\leq}$ section C<3. In other words, priority of deciding one-way road should be given to section C, the highest total point, while posterior to section A, where relatively low points are distributed. The standard on deciding one-way road suggested in this paper may be used for designating one-way road and basic data to re-establish the relevant system in the future.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.676-685
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• 1989

Optimal operating conditions of on-farm red pepper dryer were searched by using the simulation-optimization algorithm combining the drying and quality deterioration models of red pepper with Box's complex method. Determination of control variables such as air temperature, air recycle ratio and air flow rate was based on a criterion of minimizing energy consumption under the constrainst conditions that satisfied the specified color retention of carotenoids. As quality constraint was stricter, energy consumption increased and total drying time decreased with lower recycle ratio and higher air flow rate Product mixing during drying was found to be able to improve the energy efficiency and product quality. Currently used air flow rate was assessed to be increased for the optimal operation. Two stage drying at the fixed optimal air flow rate was proven to be useful means for further saying of energy consumption. In the optimal bistaged drying, the second stage began at about one third of the total drying time and low air temperature in the first stage Increased to a high value and air recycle ratio increased slightly in the second stage. Optimal control variable scheme could be explained by the dryer performance and the carotenoids destruction kinetics in red pepper drying.

• Land and Housing Review
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• v.12 no.4
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• pp.61-79
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• 2021

Despite the rapid economic growth, people's quality of life has not been improved and the regional and hierarchical disparities of it have deepened. We analysed regional differences in quality of life and it was found that non-capital regions, provinces and rural areas compared to Seoul and capital region, metropolitan cities, and urban areas respectively, show a relatively lower level of satisfaction in the quality of life. An in-depth analysis of Chungcheongnam-do province shows that the trend was similar to that of the national analysis. The quality of life satisfaction of the elderly was lower than that of the young and middle-aged, and this trend was similar regardless of region. Young people living in the Dong area showed high satisfaction with the quality of life than the middle-aged and elderly living in the Myeon area. It was observed the level of Life SOC services in urban areas have been better than the one in rural areas. However, there is no clear relationship between quality of life satisfaction and the expansion of Life SOC, therefore, it is difficult to argue that the government intervention to expand Life SOC will improve the citizen's quality of life satisfaction. The implication of the study is that the future supply policy of the Life SOC should be based on the detailed analysis of the impact on the environment, and linking with the development of various programs in progress rather than supplying a Life SOC that provides a single service. Furthermore, in rural areas it is essential to enhance user demand by combining several services in supply and to improve the efficiency of managing the services.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.25-33
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• 2020

This study was based on the research contents of previous studies. and After operatively defining public culture and arts institutions in terms of combining the characteristics of public institutions and culture and arts, the necessity of analyzing the priority of performance evaluation indicators was raised in accordance with this. The results of priority analysis based on the AHP axiom are as follows. The priorities for the performance evaluation index of public culture and arts institutions were in the order of artistry, expertise, marketing, publicity, organizational management, exchange and cooperation, management efficiency, operating system, and convenience. Based on the analysis results, the following implications were presented. First, it is necessary to first pay attention to the items of artistry that appear as the highest priority and seek strategies. Second, it is necessary to put a variety of experts in the original plan so that the audience and the public can have a high interest in this. However, in order not to exceed the 10 items recommended by the AHP axiom, we had to intentionally limit the evaluation items. Therefore, it is necessary to analyze priorities by deriving various evaluation items in subsequent studies.

• Journal of the Korean Institute of Gas
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• v.22 no.5
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• pp.53-61
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• 2018

Low-salinity water based polymerflooding (LSPF) is one of promising enhanced oil recovery (EOR) method that has the synergetic effect of combining polymer injection method and low-salinity water injection method. In order to maximize EOR efficiency, it is essential to design low-salinity water appropriately considering the properties of polymer. In this aspect, the main purpose of this study is to investigate the effect of pH and $SO_4{^{2-}}$ ion which one of PDI (Potential Determining Ion) on oil production when applying LSPF to carbonate oil reservoir. First, the stability and adsorption of polymer molecule were analyzed in different pH of injection water and $SO_4{^{2-}}$ concentration in injection water. As a result, regardless of pH and $SO_4{^{2-}}$ concentration, when $SO_4{^{2-}}$ ion was contained in injection water, the stability of polymer solution was obtained. However, from the result of polymer retention analysis, in neutral state of injection water, since $SO_4{^{2-}}$ interfered the adsorption of polymer, the adsorption thickness of polymer was thinner as $SO_4{^{2-}}$ concentration was higher. On the other hand, when injection water was acidic as pH 4, the amount of polymer adsorption increased with the injection of polymer solution, so the mobility of polymer solution was greatly lowered. From the results of wettability alteration due to low-salinity water effect, in the case of neutral injection water injected, as $SO_4{^{2-}}$ concentration was increased, more oil which attached on rock surface was detached, altering wettability from oil-wet to water-wet. On the other hand, in acidic condition, due to complex effect of rock dissolution and polymer adsorption, wettability of the entire core system was less altered relatively to neutral condition. Therefore, it was evaluated that better EOR efficiency was obtained when injecting low-salinity water based polymer solution containing high concentration of $SO_4{^{2-}}$ with neutral condition, enhancing the oil production up to 12.3% compared to low-salinity water injection method.

• Journal of Technology Innovation
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• v.26 no.3
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• pp.37-68
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• 2018

Since the 20th century, automobiles, which are the most common means of transportation, have been evolving as the use of electronic control devices and automotive semiconductors increases dramatically. Automotive semiconductors are a key component in automotive electronic control devices and are used to provide stability, efficiency of fuel use, and stability of operation to consumers. For example, automotive semiconductors include engines control, technologies for managing electric motors, transmission control units, hybrid vehicle control, start/stop systems, electronic motor control, automotive radar and LIDAR, smart head lamps, head-up displays, lane keeping systems. As such, semiconductors are being applied to almost all electronic control devices that make up an automobile, and they are creating more effects than simply combining mechanical devices. Since automotive semiconductors have a high data rate basically, a microprocessor unit is being used instead of a micro control unit. For example, semiconductors based on ARM processors are being used in telematics, audio/video multi-medias and navigation. Automotive semiconductors require characteristics such as high reliability, durability and long-term supply, considering the period of use of the automobile for more than 10 years. The reliability of automotive semiconductors is directly linked to the safety of automobiles. The semiconductor industry uses JEDEC and AEC standards to evaluate the reliability of automotive semiconductors. In addition, the life expectancy of the product is estimated at the early stage of development and at the early stage of mass production by using the reliability test method and results that are presented as standard in the automobile industry. However, there are limitations in predicting the failure rate caused by various parameters such as customer's various conditions of use and usage time. To overcome these limitations, much research has been done in academia and industry. Among them, researches using data mining techniques have been carried out in many semiconductor fields, but application and research on automotive semiconductors have not yet been studied. In this regard, this study investigates the relationship between data generated during semiconductor assembly and package test process by using data mining technique, and uses data mining technique suitable for predicting potential failure rate using customer bad data.

• Composites Research
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• v.34 no.4
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• pp.241-248
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• 2021

As the electric vehicle market grows, there is an issue of light weight vehicles to increase battery efficiency. Therefore, it is going to replace the battery module cover that protects the battery module of electric vehicles with high strength/high heat-resistant polymer composite material which has lighter weight from existing aluminum materials. It also aims to respond to the early electric vehicle market where technology changes quickly by combining 3D printing technology that is advantageous for small production of multiple varieties without restrictions on complex shapes. Based on the composite material mechanics, the critical length of glass fibers in short glass fiber (GF)/polycarbonate (PC) composite materials manufactured through extruder was derived as 453.87 ㎛, and the side feeding method was adopted to improve the residual fiber length from 365.87 ㎛ and to increase a dispersibility. Thus, the optimal properties of tensile strength 135 MPa and Young's modulus 7.8 MPa were implemented as GF/PC composite materials containing 30 wt% of GF. In addition, the filament extrusion conditions (temperature, extrusion speed) were optimized to meet the commercial filament specification of 1.75 mm thickness and 0.05 mm standard deviation. Through manufactured filaments, 3D printing process conditions (temperature, printing speed) were optimized by multi-optimization that minimize porosity, maximize tensile strength, and printing speed to increase the productivity. Through this procedure, tensile strength and elastic modulus were improved 11%, 56% respectively. Also, by post-processing, tensile strength and Young's modulus were improved 5%, 18% respectively. Lastly, using the FEA (finite element analysis) technique, the structure of the battery module cover was optimized to meet the mechanical shock test criteria of the electric vehicle battery module cover (ISO-12405), and it is satisfied the battery cover mechanical shock test while achieving 37% lighter weight compared to aluminum battery module cover. Based on this research, it is expected that 3D printing technology of polymer composite materials can be used in various fields in the future.