• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.3
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• pp.127-143
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• 2022

Recently, many attempts to run numerical ocean models in cloud computing environments have been tried actively. A cloud computing environment can be an effective means to implement numerical ocean models requiring a large-scale resource or quickly preparing modeling environment for global or large-scale grids. Many commercial and private cloud computing systems provide technologies such as virtualization, high-performance CPUs and instances, ether-net based high-performance-networking, and remote direct memory access for High Performance Computing (HPC). These new features facilitate ocean modeling experimentation on commercial cloud computing systems. Many scientists and engineers expect cloud computing to become mainstream in the near future. Analysis of the performance and features of commercial cloud services for numerical modeling is essential in order to select appropriate systems as this can help to minimize execution time and the amount of resources utilized. The effect of cache memory is large in the processing structure of the ocean numerical model, which processes input/output of data in a multidimensional array structure, and the speed of the network is important due to the communication characteristics through which a large amount of data moves. In this study, the performance of the Regional Ocean Modeling System (ROMS), the High Performance Linpack (HPL) benchmarking software package, and STREAM, the memory benchmark were evaluated and compared on commercial cloud systems to provide information for the transition of other ocean models into cloud computing. Through analysis of actual performance data and configuration settings obtained from virtualization-based commercial clouds, we evaluated the efficiency of the computer resources for the various model grid sizes in the virtualization-based cloud systems. We found that cache hierarchy and capacity are crucial in the performance of ROMS using huge memory. The memory latency time is also important in the performance. Increasing the number of cores to reduce the running time for numerical modeling is more effective with large grid sizes than with small grid sizes. Our analysis results will be helpful as a reference for constructing the best computing system in the cloud to minimize time and cost for numerical ocean modeling.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.117-120
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• 2005

인구주택총조사는 국가통계의 가장 기본이 되는 자료를 생산하는 조사로 거의 대부분의 나라에서 전수조사방식으로 정기적으로 시행해왔다. 그러나 최근 들어 일부 국가, 특히 선진국에서 응답거부가 늘고, 조사대상을 접촉하기 어려운 등 조사환경이 나빠지고 있다. 아울러 조사비용이 급격하게 증가하고 있다. 이에 각 국의 통계청에서는 이러한 상황을 인구센서스에 대한 '근본적인 도전'으로 간주하고 있다(Jensen, 2000). 심지어 독일이나 네델란드에서는 조사환경의 악화로 1990년대 이후 인구센서스를 중단한 상태이다(Bierau, 2000). 조사환경의 악화는 조사의 포괄성과 신뢰성에 대한 문제를 야기한다. 선진국들과 마찬가지로 우리나라에서도 조사환경이 빠른 속도로 악화되고 있다. 더욱이 우리의 경우 읍면동사무소 기능축소로 말미암아 과거 인구주택총조사에서 실제 조사에 도움을 주었던 행정지원이 없어짐에 따라 앞으로 조사의 어려움은 더욱 커질 것으로 보인다. 이렇듯 악화되는 조사환경변화에 대응하여 선진 국가에서는 다양한 형태의 인구센서스방식들이 모색되고 있다. 많은 나라들이 순환형 센서스보다는 행정자료를 인구주택총조사에 활용하는 방안을 모색하고 있으며, 덴마크나 핀란드 등 일부 국가에서는 이미 전혀 조사를 하지 않고 행정자료로 대부분의 인구센서스 통계를 생산하고 있다(Harala, 1996; Gaasemyr, 1999; Laihonen, 1999), 많은 나라들이 행정자료를 활용한 인구센서스 방식을 선호하는 데는 또 다른 이유가 있다. 자료의 측면에서 보면, 행정자료를 활용할 경우 매년 인구센서스 통계를 생산할 수 있다. 실제로 현재 덴마크와 핀란드는 인구센서스에 준하는 통계를 매년 생산하고 있다. 또한 이러한 자료를 바탕으로 지역통계 수요에 즉각 대처할 수 있다. 더 나아가 이와 같은 통계는 전 국민에 대한 패널자료이기 때문에 통계적 활용의 범위가 방대하다. 특히 개인, 가구, 사업체 등 사회 활동의 주체들이 어떻게 변화하는지를 추적할 수 있는 자료를 생산함으로써 다양한 인과적 통계분석을 할 수 있다. 행정자료를 활용한 인구센서스의 이러한 특징은 국가의 교육정책, 노동정책, 복지정책 등 다양한 정책을 정확한 자료를 근거로 수립할 수 있는 기반을 제공한다(Gaasemyr, 1999). 이와 더불어 행정자료 기반의 인구센서스는 비용이 적게 드는 장점이 있다. 예를 들어 덴마크나 핀란드에서는 조사로 자료를 생산하던 때의 1/20 정도 비용으로 행정자료로 인구센서스의 모든 자료를 생산하고 있다. 특히, 최근 모든 행정자료들이 정보통신기술에 의해 데이터베이스 형태로 바뀌고, 인터넷을 근간으로 한 컴퓨터네트워크가 발달함에 따라 각 부처별로 행정을 위해 축적한 자료를 정보통신기술로 연계${cdot}$통합하면 막대한 조사비용을 들이지 않더라도 인구센서스자료를 적은 비용으로 생산할 수 있는 근간이 마련되었다. 이렇듯 행정자료 기반의 인구센서스가 많은 장점을 가졌지만, 그렇다고 모든 국가가 당장 행정자료로 인구센서스를 대체할 수 있는 것은 아니다. 행정자료로 인구센서스통계를 생산하기 위해서는 각 행정부서별로 사용하는 행정자료들을 연계${cdot}$통합할 수 있도록 국가사회전반에 걸쳐 행정 체제가 갖추어져야 하기 때문이다. 특히 모든 국민 개개인에 관한 기본정보, 개인들이 거주하며 생활하는 단위인 개별 주거단위에 관한 정보가 행정부에 등록되어 있고, 잘 정비되어 있어야 하며, 정보의 형태 또한 서로 연계가 가능하도록 표준화되어있어야 한다. 이와 더불어, 현재 인구센서스에서 표본조사를 통해 부가적으로 생산하는 경제활동통계를 생산하기 위해서는 개인이 속한 사업체를 파악할 수 있도록 모든 사업체가 등록되어 있고, 개인의 경제활동과 관련된 각종 정보들이 사업체에 잘 기록 및 정비되어 있어야 한다. 따라서 행정자료 기반의 인구센서스통계생산은 단지 국가의 통계뿐만 아니라 행정조직과 행정체계를 정비하고, 개인과 사업체의 등록체계를 정비하며, 사업체의 개인에 관한 정보를 정비하여 표준화하는 막대한 작업을 수반한다. 이런 이유에서 대부분의 국가들은 장래에 행정자료 기반의 인구센서스통계생산을 목표로 하되, 당장은 행정자료를 인구센서스에 보조적 수단을 사용하는 데 노력을 기울이고 있다. 우리나라의 경우 행정자료를 인구주택총조사에 활용할 수 있는 몇 가지 중요한 기반을 갖추고 있다. 첫째, 1962년부터 시행한 주민등록제도가 있다. 주민등록제도는 모든 국민 개개인을 파악할 수 있는 주민등록번호를 갖추고 있으며 40년 이상 제도화되어 오류가 거의 없는 편이다. 둘째, 세계 10위권 내에 들 정도로 높은 우리나라의 정보화 수준과 2000년부터 시작된 전자정부사업으로 행정자료를 연계${cdot}$통합할 수 있는 기반이 잘 갖추어져 있다. 반면, 우리나라 행정자료 가운데 주거(생활)단위와 사업체를 파악할 수 있는 자료는 매우불완전하다. 대표적으로 인구센서스통계의 주요한 단위인 가구를 파악할 수 있는 수준으로 주소체계가 정비되어 있지 않으며, 많은 사업체, 특히 소규모 사업 가운데 등록되어 있지 않거나 등록오류가 많은 편이다. 이외에도 과세대장, 토지대장 등 많은 행정자료가 아직은 불완전하여 이들을 직접 연계하기에 어렵다. 행정자료를 연계하기 위해서는 모든 자료를 정비하고 표준화하여 실제 행정에 활용하여야 하기 때문에 행정적으로 많은 노력과 시간이필요하다. 따라서 현재는 손쉬운 부분에서부터 인구주택총조사에 행정자료를 활용하고, 앞으로 활용 과정을 거치면서 행정자료를 정비하고 표준화하는 장기적인 방안을 마련할 필요가 있다.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.457-466
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• 2002

An artificial neural network was applied to predict compressive strength, slump value and mix proportion of a concrete. Standard mixed tables were trained and estimated, and the results were compared with those of the experiments. To consider variabilities of material properties, the standard mixed fables from two companies of Ready Mixed Concrete were used. And they were trained with the neural network. In this paper, standard back propagation network was used. The mix proportion factors such as water cement ratio, sand aggregate ratio, unit water, unit cement, unit weight of sand, unit weight of crushed sand, unit coarse aggregate and air entraining admixture were used. For the arrangement on the approval of prediction of mix proportion factor, the standard compressive strength of $180kgf/cm^2{\sim}300kgf/cm^2$, and target slump value of 8 cm, 15 cm were used. For the arrangement on the approval of prediction of compressive strength and slump value, the standard compressive strength of $210kgf/cm^2{\sim}240kgf/cm^2$, and target slump value of 12 cm and 15 cm wore used because these ranges are most frequently used. In results, in the prediction of mix proportion factor, for all of the water cement ratio, sand aggregate ratio, unit water, unit cement, unit weight of sand, unit weight of crushed sand, unit coarse aggregate, air entraining admixture, the predicted values and the values of standard mixed tables were almost the same within the target error of 0.10 and 0.05, regardless of two companies. And in the prediction of compressive strength and slump value, the predicted values were converged well to the values of standard mixed fables within the target error of 0.10, 0.05, 0.001. Finally artificial neural network is successfully applied to the prediction of concrete mixture and compressive strength.

• Journal of the Korea Society of Computer and Information
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• v.18 no.2
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• pp.149-156
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• 2013

In this paper, the Constitutional Court's ruling through the SNS was virtually guaranteed the freedom of election campaign through, though, still a large portion of campaign restrictions on public election law provisions exist to this forward in the election is likely to cause a lot of legal problems. In this paper, the Constitutional Court's ruling through the SNS was virtually guaranteed the freedom of election campaign through, though, still a large portion of campaign restrictions on public election law provisions exist to this forward in the election is likely to cause a lot of legal problems. Moreover, in the mean time the campaign and which in the course of the election campaign through the SNS, the infinite potential of the growing point than any point spread from the SNS and freedom of election campaign through public election law with regard to the limitation of the diffusion of false facts, awards, a number of problems are likely to occur. You've been in this business and disseminate false guilt disparage precandidacy for true-false, as well. He should be able to reach a specific goal you want to defeat through the dissemination of information which is specified as a crime for this strictly for the fact that disseminate false, rather than to interpret it is the judgment of the Court in that judgment against have been made. Therefore, this strict interpretation of the law and the need to revise or delete before I would like to discuss about. The legislation would repeal the cull of Ron sang first of all point out the issue through analytics. First, the purpose of the data protection Act provides limited interpretation to fit in this world of sin. Secondly, this sin is committed for the purpose of prevention, since the purpose of the objective in this case of sin and the need to interpret strictly. Why I am the Internet space in the case of so-called tweets from followers, this means in some cases done without a lot of the stars because of this, there will be a limit to the punishment of sin, this is obvious. And, in the long-awaited Constitutional Court ensures the freedom of election campaign through SNS and free election in the country, even in the limited sense interpretation opens the chapter of communication is needed. This ensured the freedom of expression will be highly this is a mature civil society that will be imperative.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.5
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• pp.50-60
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• 2010

For the last half a century, the personal computer and software industries have been prosperous due to the incessant evolution of computer systems. In the 21st century, the embedded system market has greatly increased as the market shifted to the mobile gadget field. While a lot of multimedia gadgets such as mobile phone, navigation system, PMP, etc. are pouring into the market, most industrial control systems still rely on 8-bit micro-controllers and simple application software techniques. Unfortunately, the technological barrier which requires additional investment and higher quality manpower to overcome, and the business risks which come from the uncertainty of the market growth and the competitiveness of the resulting products have prevented the companies in the industry from taking advantage of such fancy technologies. However, high performance, low-power and low-cost hardware and software platforms will enable their high-technology products to be developed and recognized by potential clients in the future. This paper presents such a platform for industrial embedded systems. The platform was designed based on Telechips TCC8300 multimedia processor which embedded a variety of parallel hardware for the implementation of multimedia functions. And open-source Embedded Linux, TinyX and GTK+ are used for implementation of GUI to minimize technology costs. In order to estimate the expected performance and power consumption, the performance improvement and the power consumption due to each of enabled hardware sub-systems including YUV2RGB frame converter are measured. An analytic model was devised to check the feasibility of a new application and trade off its performance and power consumption. The validity of the model has been confirmed by implementing a real target system. The cost can be further mitigated by using the hardware parts which are being used for mass production products mostly in the cell-phone market.

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.239-250
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• 2020

The purpose of this paper is to explore the influence of the "contextualization" effect of web celebrity live broadcast on the e-commerce platform on consumers' perception of product value, risk and purchase intention. Live in this paper, using Taobao shopping consumers as the research object, the survey method, questionnaire survey is adopted, the form through the questionnaire and distributed network, a live in order to further validation of web celebrity effect of contextualized actual influence on consumer purchase intention, questionnaire design the Likert scale, seven and recycling questionnaire analysis using the statistical software SPSS 23.0 and AMOS 22.0 after processing the data. After determining the reliability and validity of the questionnaire, the exploratory factor analysis was used to verify the hypothesis and calculate the actual adjustment degree of the "contextualization" effect of web celebrity live broadcasting on consumers' purchase intention. The research results of this paper are summarized as follows :(1) consumers' perceived value of products can significantly positively affect their purchase intention, while perceived risk has a significantly negative impact on their purchase intention; (2) consumers' trust and purchase intention to products are regulated by the "contextualization" of web celebrity live broadcast. Specifically, for web celebrity live broadcasting with good "contextualization" effect, the perceived value of consumer products has a positive impact on product trust, which is higher than that of web celebrity live broadcasting with poor "contextualization" effect. In terms of resolving consumers' perceived risks to products, web celebrity live broadcast with good "contextualization" effect is also significantly better than web celebrity live broadcast with poor "contextualization" effect. Based on empirical analysis, this paper concludes that web celebrity live broadcasting will become a new breakthrough for the sustainable growth of the e-commerce industry, and puts forward Suggestions on the e-commerce marketing mode and the transformation of web celebrity live broadcasting industry.

• The Korean Journal of Air & Space Law and Policy
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• v.32 no.1
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• pp.83-138
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• 2017

Korea-China FTA entered into force on the 20th of December 2015, and one year elapsed after its effectuation as the FTA with China, our country's largest trading partner. Therefore, this study looks at the trends of air transport trade between Korea and China, and examines the contents of concessions to the air transport services sector in Korea-China FTA, and analyzes the impact on the air transport sector by Korea-China FTA, and proposes our country's aviation policy direction in order to respond to such impact. In 2016 the trends of air transport trade between Korea and China are as follows : The export amount of air transport trade to China was 40.03 billion dollars, down by 9.3% from the last year, and occupied 32.2% of the total export amount to China. The import amount of air transport trade from China was 24.26 billion dollars, down by 9.1% from the last year, and occupied 27.7% of the total import amount from China. The contents of concessions to the air transport services sector in Korea-China FTA are as follows : China made concessions to the aircraft repair and maintenance services and the computer reservation system services with limitations on market access and national treatment in the air transport services sector of the China Schedule of Specific Commitments of Korea-China FTA Chapter 8 Annex. Korea made concessions to the computer reservation system services, selling and marketing of air transport services, and aircraft repair and maintenance without limitations on market access and national treatment in the air transport services sector of the Korea Schedule of Specific Commitments of Korea-China FTA Chapter 8 Annex. The impact on the air transport sector by Korea-China FTA are as follows : As for the impact on the air passenger market, in 2016 the arrival passengers of the international flight from China were 9.96 million, up by 20.6% from the last year, and the departure passengers to China were 9.90 million, up by 34.8% from the last year. As for the impact on the air cargo market, in 2016 the exported goods volumes of air cargo to China were 105,220.2 tons, up by 6.6% from the last year, and imported goods volumes from China were 133,750.9 tons, up by 12.3% from the last year. Among the major items of exported air cargo to China, the exported goods volumes of benefited items in the Tariff Schedule of China of Korea-China FTA were increased, and among the major items of imported air cargo from China, the imported goods volumes of benefited items in the Tariff Schedule of Korea of Korea-China FTA were increased. As for the impact on the logistics market, in 2016 the handling performance of exported air cargo to China by domestic forwarders were 119,618 tons, down by 2.1% from the last year, and the handling performance of imported air cargo from China were 79,430 tons, down by 4.4% from the last year. In 2016 the e-commerce export amount to China were 109.16 million dollars, up by 27.7% from the last year, and the e-commerce import amount from China were 89.43 million dollars, up by 72% from the last year. The author proposes the aviation policy direction of Korea according to Korea-China FTA as follows : First, the open skies between Korea and China shall be pushed ahead. In June 2006 Korea and China concluded the open skies agreement within the scope of the third freedom and fourth freedom of the air for passenger and cargo in Sandong Province and Hainan Province of China, and agreed the full open skies of flights between the two countries from the summer season in 2010. However, China protested against the interpretation of the draft of the memorandum of understanding to the air services agreement, therefore the further open skies did not take place. Through the separate aviation talks with China from Korea-China FTA, the gradual and selective open skies of air passenger market and air cargo market shall be pushed ahead. Second, the competitiveness of air transport industry and airport shall be secured. As for the strengthening methods of the competitiveness of Korea's air transport industry, the support system for the strengthening of national air carriers' competitiveness shall be prepared, and the new basis for competition of national air carriers shall be made, and the strategic network based on national interest shall be built. As for the strengthening methods of the competitiveness of Korea's airports, particularly Incheon Airport, the competitiveness of the network for aviation demand creation shall be strengthened, and the airport facilities and safety infrastructure shall be expanded, and the new added value through the airport shall be created, and the world's No.1 level of services shall be maintained. Third, the competitiveness of aviation logistics enterprises shall be strengthened. As for the strengthening methods of the competitiveness of Korea's aviation logistics enterprises, as the upbringing strategy of higher added value in response to the industry trends changes, the new logistics market shall be developed, and the logistics infrastructure shall be expanded, and the logistics professionals shall be trained. Additionally, as the expanding strategy of global logistics market, the support system for overseas investment of logistics enterprises shall be built, and according to expanding the global transport network, the international cooperation shall be strengthened, and the network infrastructure shall be secured. As for the strengthening methods of aviation logistics competitiveness of Incheon Airport, the enterprises' demand of moving in the logistics complex shall be responded, and the comparative advantage in the field of new growth cargo shall be preoccupied, and the logistics hub's capability shall be strengthened, and the competitiveness of cargo processing speed in the airport shall be advanced. Forth, in the subsequent negotiation of Korea-China FTA, the further opening of air transport services sector shall be secured. In the subsequent negotiation being initiated within two years after entry into force of Korea-China FTA, it is necessary to ask for the further opening of the concessions of computer reservation system services, and aircraft repair and maintenance services in which the concessions level of air transport services sector by China is insufficient compared to the concessions level in the existing FTA concluded by China. In conclusion, in order to respond to the impact on Korea's air passenger market, air cargo market and aviation logistics market by Korea-China FTA, the following policy tasks shall be pushed ahead : Taking into consideration of national air carriers' competitiveness and nation's benefits, the gradual and selective open skies shall be pushed ahead, and the support system to strengthen the competitiveness of air transport industry and airport shall be built, and entry into aviation logistics market by logistics enterprises shall be expanded, and the preparations to ask for the further opening of air transport services sector, low in the concessions level by China shall be made.

• Journal of Intelligence and Information Systems
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• v.27 no.1
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• pp.191-207
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• 2021

Up to this day, mobile communications have evolved rapidly over the decades, mainly focusing on speed-up to meet the growing data demands of 2G to 5G. And with the start of the 5G era, efforts are being made to provide such various services to customers, as IoT, V2X, robots, artificial intelligence, augmented virtual reality, and smart cities, which are expected to change the environment of our lives and industries as a whole. In a bid to provide those services, on top of high speed data, reduced latency and reliability are critical for real-time services. Thus, 5G has paved the way for service delivery through maximum speed of 20Gbps, a delay of 1ms, and a connecting device of 106/㎢ In particular, in intelligent traffic control systems and services using various vehicle-based Vehicle to X (V2X), such as traffic control, in addition to high-speed data speed, reduction of delay and reliability for real-time services are very important. 5G communication uses high frequencies of 3.5Ghz and 28Ghz. These high-frequency waves can go with high-speed thanks to their straightness while their short wavelength and small diffraction angle limit their reach to distance and prevent them from penetrating walls, causing restrictions on their use indoors. Therefore, under existing networks it's difficult to overcome these constraints. The underlying centralized SDN also has a limited capability in offering delay-sensitive services because communication with many nodes creates overload in its processing. Basically, SDN, which means a structure that separates signals from the control plane from packets in the data plane, requires control of the delay-related tree structure available in the event of an emergency during autonomous driving. In these scenarios, the network architecture that handles in-vehicle information is a major variable of delay. Since SDNs in general centralized structures are difficult to meet the desired delay level, studies on the optimal size of SDNs for information processing should be conducted. Thus, SDNs need to be separated on a certain scale and construct a new type of network, which can efficiently respond to dynamically changing traffic and provide high-quality, flexible services. Moreover, the structure of these networks is closely related to ultra-low latency, high confidence, and hyper-connectivity and should be based on a new form of split SDN rather than an existing centralized SDN structure, even in the case of the worst condition. And in these SDN structural networks, where automobiles pass through small 5G cells very quickly, the information change cycle, round trip delay (RTD), and the data processing time of SDN are highly correlated with the delay. Of these, RDT is not a significant factor because it has sufficient speed and less than 1 ms of delay, but the information change cycle and data processing time of SDN are factors that greatly affect the delay. Especially, in an emergency of self-driving environment linked to an ITS(Intelligent Traffic System) that requires low latency and high reliability, information should be transmitted and processed very quickly. That is a case in point where delay plays a very sensitive role. In this paper, we study the SDN architecture in emergencies during autonomous driving and conduct analysis through simulation of the correlation with the cell layer in which the vehicle should request relevant information according to the information flow. For simulation: As the Data Rate of 5G is high enough, we can assume the information for neighbor vehicle support to the car without errors. Furthermore, we assumed 5G small cells within 50 ~ 250 m in cell radius, and the maximum speed of the vehicle was considered as a 30km ~ 200 km/hour in order to examine the network architecture to minimize the delay.

• Cartoon and Animation Studies
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• s.22
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• pp.47-63
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• 2011

Recently, contemporary cultural contents have been shown its diversity changes followed by the birth of new media platforms with consumers' new needs in the global market. Also, developments of Internet and computer system networks are the main contributors of making this changes happened rapidly. This study aims to know that how to usefully use those new media platforms through the great example of stop-motion animation music video by analyzing its production and marketing process. The music video production had been focused to be completed with high quality by adjusting the production process economically in spite of the relatively short period(less than one month)from its crank-up to the deadline. Because the production was planned that main characters lead the whole story, the creative team had been tried to reduce the production hours by commonly use the same mold when they make original clay models by collecting the similarities of characters' appearances. By using CG technic, could overcome the visual monotonous from the similarities which inferred above. Also, the repeated rhythm in the music video, the similar scenes of backgrounds were commonly used by copy of the original scene. At the point of directing, the creative team considered both economical and art aspects for the quality work. In details, they divided the scenes into foreground and background, and removed unnecessary parts to save the production hours and budget but make depth of fields in the scenes. Except the viral marketing purposes, was searching for the methods to compensate the production cost. For this, the characters in the music video dressed the same T-shirts which are world-cup logo on, and those were designed for the sale after released the music video. Even the result of the sales was not enough to satisfied, it was estimated a great attempt to the domestic animation industry.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.67-72
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• 2000

Background :The authors have developed a Digital image chart(DIC) and digital Radiotherapy Record System (DRRS). We have evaluated the DIC and DRRS for reliability, usefulness, ease of use, and efficiency. Materials and Methods :The basic design of the DIC and DRRS was to build an digital image database of radiation therapy Patient records for a more efficient and timely flow of critical image information throughout the department. This system is a submit of comprehensive radiation oncology management system (C-ROMS) and composed of a picture archiving and communication system (PACS), a radiotherapy information database, and a radiotherapy imaging database. The DIC and DRRS were programmed using Delphi under a Windows 95 environment and is capable of displaying the digital images of patients identification photos, simulation films, radiotherapy setup, diagnostic radiology images, gross lesion Photos, and radiotherapy Planning isodose charts with beam arrangements. Twenty-three clients in the department are connected by Ethernet (10 Mbps) to the central image server (Sun Ultra-sparc 1 workstation). Results :From the introduction of this system in February 1998 through December 1999, we have accumulated a total of 15,732 individual images for 2,556 patients. We can organize radiation therapy in a 'paperless' environment in 120 patients with breast cancer. Using this system, we have succeeded in the prompt, accurate, and simultaneous access to patient care information from multiple locations throughout the department. This coordination has resulted in improved operational efficiency within the department. Conclusion :The authors believe that the DIC and DRRS has contributed to the improvement of radiation oncology department efficacy as well as to time and resource savings by providing necessary visual information throughout the department conveniently and simultaneously. As a result, we can also achieve the 'paperless' and 'filmless' practice of radiation oncology with this system.