• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.115-122
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• 2014

In this paper, reliability is secured by sensing a post-program resistance of several tens of kilo ohms and restricting a read current flowing over an unblown eFuse within $100{\mu}A$ since RWL driver and BL pull-up load circuits using a regulated voltage of V2V ($=2V{\pm}10%$) are proposed to have a wide operating voltage range for eFuse OTP memory. Also, when a comparison of a cell array of 1 row ${\times}$ 32 columns with that of 4 rows ${\times}$ 8 columns is done, the layout size of 4 rows ${\times}$ 8 columns is smaller with $187.065{\mu}m{\times}94.525{\mu}m$ ($=0.01768mm^2$) than that of 1 row ${\times}$ 32 columns with $735.96{\mu}m{\times}61.605{\mu}m$ ($=0.04534mm^2$).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5452-5457
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• 2012

It is saving material cost and construction cost by replacing conventional building materials, and It has advantages for aesthetic value. In the Europe, the United States, Japan and other country research about BIPV is actively being carried out and marketability is also being infinity expanding. Arch type PV systems efficiency characteristics is different depending on PV array's directly connection, parallel connection and arches angle, but is a lack of analysis on this nowadays. When the arch type PV system design up, they consider about aesthetic value and they didn't consider about generation efficiency. In this paper, we try to improve the efficiency through optimization of arch type PV system and estimation of the efficiency parameters of the arch type PV system, such as latitude, longitude, temperature, insolation, arch angle and each kind loss from system organization. For improving Arched PV system efficiency, proposed multiple control inverter system, and using simulation tool of Arched PV system "Solar pro", flat-plate type and many arch type PV system configuration the driving characteristics were compared and analyzed.

• Journal of the Korean Geographical Society
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• v.47 no.5
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• pp.791-808
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• 2012

This study sets out to assess achievement of two series of publication titled "the Geography of Korea", which established itself as the most representative publication on Korea's geography. For assessment, this study selected Delphi method to survey Korean geographical professionals on the publication by requesting respondents to rate the adequacy of its: publishing system, production team organization, array of topics, target reader, classification of regions, and use of visual materials. The results showed the respondents highly appreciated the significance of the publications and generally agreed that the past publications had adequate level of: publication frequency, time allowed for writing, number of pages, selection criteria of authors, range of topics, region classification schemes. On the other hand, dissatisfaction from the respondents came from the lack of chief supervisor over each section or the whole publication. The geographers also stressed the need to enhance the publication's accessibility to the wider public by adopting easier writings and also requested diversification of visual aid design. This study also examined the difference between respondent groups by occupations and by past involvement in the publication. The result of this study can serve as a foundation to identify the desirable direction of future publications on "the Geography of Korea".

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.11
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• pp.51-62
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• 2003

This paper presents a novel survivor memeory management and decoding techniques with sequential backward state transition control in the trace back Viterbi decoder. The Viterbi algorithm is an maximum likelihood decoding scheme to estimate the likelihood of encoder state for channel error detection and correction. This scheme is applied to a broad range of digital communication such as intersymbol interference removing and channel equalization. In order to achieve the area-efficiency VLSI chip design with high throughput in the Viterbi decoder in which recursive operation is implied, more research is required to obtain a simple systematic parallel ACS architecture and surviver memory management. As a method of solution to the problem, this paper addresses a progressive decoding algorithm with sequential backward state transition control in the trace back Viterbi decoder. Compared to the conventional trace back decoding techniques, the required total memory can be greatly reduced in the proposed method. Furthermore, the proposed method can be implemented with a simple pipelined structure with systolic array type architecture. The implementation of the peripheral logic circuit for the control of memory access is not required, and memory access bandwidth can be reduced Therefore, the proposed method has characteristics of high area-efficiency and low power consumption with high throughput. Finally, the examples of decoding results for the received data with channel noise and application result are provided to evaluate the efficiency of the proposed method.

• 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.

• Fire Science and Engineering
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• v.26 no.5
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• pp.41-47
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• 2012

As a core process in the manufacture of state-of-the-art industrial technologies such as semiconductor and LCD, a clean room is the most important process which can affect the performance and quality of products drastically. Nevertheless, scientific research on comprehensive safety measures from a fire protection standpoint is not being carried out in Korea. This study aims to derive measures to improve smoke control systems by identifying performance and problems of smoke systems installed in clean rooms as an LCD manufacturing process and analyzing fire and evacuation simulations considering several scenarios. As a result of analysis of fires and smoke in a clean roomas an LCD manufacturing process, it is found to be necessary to stop air handling units through interlocking in case of a fire and exhaust smoke out of the room through the top of FAB in consideration of buoyancy of smoke. It is also found to be necessary to install quick response sprinkler heads and accessories to accelerate the response time, because the heat-accumulating performance of sprinkler heads decreases in this application. Despite its low density of dwelling due to the automation process, clean room is characterized by an array of complex production equipment and working environment requiring dustproof clothes, which makes it difficult to acquire evacuation safety performance. Thus, thorough control of danger factors in processes and periodic education and training are required. It is also necessary to establish a level of domestic technologies equivalent to the level of standards of advanced countries in fire protection.

• Tunnel and Underground Space
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• v.17 no.4
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• pp.266-284
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• 2007

Recently, many efforts have been made to construct the first unlined tunnel, without in-situ concrete lining, in Korea. However, the lack of reliability in the performance of shotcrete as permanent tunnel support prevented from its realization. Shotcrete has been regarded to have significant problems in field application and long term performance because of unsatisfactory strength level and durability compared to those of European countries. In this study, the high strength shotcrete satisfying compressive strength over 40 MPa and flexural strength over 4.5 MPa was developed from optimized mix design. The type of accelerators and the amount of silica fume were selected as the main factors in mixing process and the analyses were carried out up to the elapsed time of 2 years. In order to evaluate the short term durability of shotcrete, an array of laboratory test consisting of freeze-thaw, carbonation chloride penetration and permeability test was performed. For long-term durability tests, specimens have been put in an operated highway tunnel to expose them to the similar environment when they are actually used as an unlined tunnel support. From the strength and durability tests, it was found that only alkali-free based accelerator satisfied the target strength of this study and also, the developed shotcrete showed very high performance in its durability.

• Progress in Medical Physics
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• v.23 no.3
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• pp.162-168
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• 2012

In proton therapy, in vivo dose verification is one of the most important parts to fully utilize characteristics of proton dose distribution concentrating high dose with steep gradient and guarantee the patient safety. Currently, in order to image the proton dose distribution, a prompt gamma distribution detection system, which consists of an array of multiple CsI(Tl) scintillation detectors in the vertical direction, a collimator, and a multi-channel DAQ system is under development. In the present study, the optimal design of prompt gamma distribution detection system was studied by Monte Carlo simulations using the MCNPX code. For effective measurement of high-energy prompt gammas with enough imaging resolution, the dimensions of the CsI(Tl) scintillator was determined to be $6{\times}6{\times}50mm^3$. In order to maximize the detection efficiency for prompt gammas while minimizing the contribution of background gammas generated by neutron captures, the hole size and the length of the collimator were optimized as $6{\times}6mm^2$ and 150 mm, respectively. Finally, the performance of the detection system optimized in the present study was predicted by Monte Carlo simulations for a 150 MeV proton beam. Our result shows that the detection system in the optimal dimensions can effectively measure the 2D prompt gamma distribution and determine the beam range within 1 mm errors for 150 MeV proton beam.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.253-263
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• 1993

Climatological informations have not been fully utilized by agricultural research and extension workers in Korea due mainly to inaccessbilty to the archived climate data. This study was initiated to improve access to historical climate data gathered from 72 weather stations of Korea Meteorological Administration for agricultural applications by using a microcomputer-based methodology. The climatological elements include daily values of average, maximum and minimum temperature, relative humidity, average and maximum wind speed, wind direction, evaporation, precipitation, sunshine duration and cloud amount. The menu-driven, user-friendly data retrieval system(CLIDAS) provides quick summaries of the data values on a daily, weekly and monthly basis and selective retrieval of weather records meeting certain user specified critical conditions. Growing degree days and potential evapotranspiration data are derived from the daily climatic data, too. Data reports can be output to the computer screen, a printer or ASCII data files. CLIDAS can be run on any IBM compatible machines with Video Graphics Array card. To run the system with the whole database, more than 50 Mb hard disk space should be available. The system can be easily upgraded for further expansion of functions due to the module-structured design.

• Steel and Composite Structures
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• v.34 no.5
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• pp.681-698
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• 2020

The paper addresses contribution to the modeling and optimization of major machinability parameters (cutting force, surface roughness, and tool wear) in finish dry hard turning (FDHT) for machinability evaluation of hardened AISI grade die steel D₃ with PVD-TiN coated (Al₂O₃-TiCN) mixed ceramic tool insert. The turning trials are performed based on Taguchi's L₁₈ orthogonal array design of experiments for the development of regression model as well as adequate model prediction by considering tool approach angle, nose radius, cutting speed, feed rate, and depth of cut as major machining parameters. The models or correlations are developed by employing multiple regression analysis (MRA). In addition, statistical technique (response surface methodology) followed by computational approaches (genetic algorithm and particle swarm optimization) have been employed for multiple response optimization. Thereafter, the effectiveness of proposed three (RSM, GA, PSO) optimization techniques are evaluated by confirmation test and subsequently the best optimization results have been used for estimation of energy consumption which includes savings of carbon footprint towards green machining and for tool life estimation followed by cost analysis to justify the economic feasibility of PVD-TiN coated Al₂O₃+TiCN mixed ceramic tool in FDHT operation. Finally, estimation of energy savings, economic analysis, and sustainability assessment are performed by employing carbon footprint analysis, Gilbert approach, and Pugh matrix, respectively. Novelty aspects, the present work: (i) contributes to practical industrial application of finish hard turning for the shaft and die makers to select the optimum cutting conditions in a range of hardness of 45-60 HRC, (ii) demonstrates the replacement of expensive, time-consuming conventional cylindrical grinding process and proposes the alternative of costlier CBN tool by utilizing ceramic tool in hard turning processes considering technological, economical and ecological aspects, which are helpful and efficient from industrial point of view, (iii) provides environment friendliness, cleaner production for machining of hardened steels, (iv) helps to improve the desirable machinability characteristics, and (v) serves as a knowledge for the development of a common language for sustainable manufacturing in both research field and industrial practice.