• 한국통신학회논문지
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• 제40권12호
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• pp.2530-2538
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• 2015

깊이맵은 색채 영상과 달리 색상 정보가 아닌 깊이 정보가 픽셀 값을 이루고 있어서 색차가 크더라도 비슷한 거리에 있으면 유사한 픽셀 값으로 나타난다. 또한 색채 영상은 미세한 영역에서 단계적으로 값이 변하면서 대상의 윤곽을 나타내지만 깊이맵은 픽셀 값이 계단식으로 변하여 픽셀 값이 변하는 지점에서 급변하는 경향이 있다. 이러한 깊이맵의 특성상 경계 영역과 그 외의 영역으로 크게 영상의 영역을 구분 할 수 있고, 전송 시 나타나는 오류에 대해 각 영역에 효과적으로 적용 될 수 있는 오류 은닉 방법이 필요하다. 본 연구에서는 깊이맵의 경계 방향에 따라 영역을 구분하고 각 영역의 값이 변화하는 방향성에 맞추어 적응적으로 오류가 은닉 될 수 있는 방법을 적용하여 깊이맵을 복구한다. 복구된 깊이맵은 다시점 영상과 함께 합성하여 새로운 중간 시점 영상을 만들고 이를 객관적 화질평가 방법을 통해 평가한다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2014년도 하계학술대회
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• pp.166-168
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• 2014

Coarse-grained reconfigurable architectures (CGRAs) present a potential of high compute throughput with energy efficiency. A CGRA consists of an array of functional units (FU), which communicate with each other through an interconnect network containing transmission nodes and register files. To achieve high performance from the software solutions mapped onto CGRAs, modulo scheduling of loops is generally employed. One of the key challenges in modulo scheduling for CGRAs is to explicitly handle routings of operands from a source to a destination operations through various routing resources. Existing modulo schedulers for CGRAs are slow because finding a valid routing is generally a searching problem over a large space, even with the guidance of well-defined cost metrics. Applications in traditional embedded multimedia domains are regarded relatively tolerant to a slow compile time in exchange of a high quality solution. However, many rapidly growing domains of applications, such as 3D graphics, require a fast compilation. Entrances of CGRAs to these domains have been blocked mainly due to its long compile time. We attack this problem by utilizing patternized routes, for which resources and time slots for a success can be estimated in advance when a source operation is placed. By conservatively reserving predefined resources at predefined time slots, future routings originated from the source operation are guaranteed. Experiments on a real-world 3D graphics benchmark suite show that our scheduler improves the compile time up to 6000 times while achieving average 70% throughputs of the state-of-art CGRA modulo scheduler, edge-centric modulo scheduler (EMS).

• 한국농공학회논문집
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• 제62권2호
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• pp.39-52
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• 2020

A high quality, long-term, high-resolution precipitation dataset is an essential in climate analyses and global water cycles. Rainfall data from station observations are inadequate over many parts of the world, especially North Korea, due to non-existent observation networks, or limited reporting of gauge observations. As a result, satellite-based rainfall estimates have been used as an alternative as a supplement to station observations. The Climate Hazards Group Infrared Precipitation (CHIRP) and CHIRP combined with station observations (CHIRPS) are recently produced satellite-based rainfall products with relatively high spatial and temporal resolutions and global coverage. CHIRPS is a global precipitation product and is made available at daily to seasonal time scales with a spatial resolution of 0.05° and a 1981 to near real-time period of record. In this study, we analyze the applicability of CHIRPS data on the Korean Peninsula by supplementing the lack of precipitation data of North Korea. We compared the daily precipitation estimates from CHIRPS with 81 rain gauges across Korea using several statistical metrics in the long-term period of 1981-2017. To summarize the results, the CHIRPS product for the Korean Peninsula was shown an acceptable performance when it is used for hydrological applications based on monthly rainfall amounts. Overall, this study concludes that CHIRPS can be a valuable complement to gauge precipitation data for estimating precipitation and climate, hydrological application, for example, drought monitoring in this region.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1863-1871
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• 2012

기존의 OSS의 활용은 운영체제나 DBMS와 같은 시스템 애플리케이션의 사용이 주를 이루었다. 그러나 현재 많은 기업에서 시스템 소프트웨어가 아닌 응용 애플리케이션 중심으로 OSS를 활용하려고 한다. 그러나 OSS를 활용한 응용 애플리케이션 개발을 위해서는 기반이 되는 OSS의 선정이 무엇보다 중요하다. 기존의 OSS 평가 연구의 범위는 전체 OSS 품질을 포함하고 있다. 그러므로 OSS 선정에 대한 평가 연구는 미흡하다. 또한 평가의 결과는 정량적인 측정보다 정성적인 측정에 기반하고 있다. 본 연구에서는 기존의 OSS 평가지표들 중 선정을 위한 지표들만을 도출하고 이를 기반으로 프로젝트 특징에 따라 정량적인 평가가 가능한 평가지표를 제안한다. 제안하는 평가지표는 OSS 커뮤니티 내의 정보만을 가지고 평가할 수 있는 초기평가지표와 정량적인 측정이 가능한 상세평가지표로 구분하여 제안한다. 이를 통해 OSS 선정 시 정량적인 점수와 지표를 통해 객관적인 근거를 제공한다.

• Journal of Multimedia Information System
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• 제1권1호
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• pp.67-75
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• 2014

Nowadays as video services grow rapidly, it is important for the service providers to provide customized services. Video ranking plays a key role for the service providers to attract the subscribers. In this paper we propose a weekly video ranking mechanism based on the quantified user engagement. The traditional QoE ranking mechanism is relatively subjective and usually is accomplished by grading, while QoS is relatively objective and is accomplished by analyzing the quality metrics. The goal of this paper is to establish a ranking mechanism which combines the both advantages of QoS and QoE according to the third-party data collection platform. We use data mining method to classify and analyze the collected data. In order to apply into the actual situation, we first group the videos and then use the regression tree and the decision tree (CART) to narrow down the number of them to a reasonable scale. After that we introduce the analytic hierarchy process (AHP) model and use Elo rating system to improve the fairness of our system. Questionnaire results verify that the proposed solution not only simplifies the computation but also increases the credibility of the system.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권2호
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• pp.132-140
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• 2002

This paper presents an ARM-based SOC bus transaction verification IP and the usage experiences in SOC designs. The verification IP is an AMBA AHB protocol checker, which captures legal AHB transactions in FSM-style signal sequence checking routines. This checker can be considered as a reusable verification IP since it does not change unless the bus protocol changes. Our AHB protocol checker is designed to be scalable to any number of AHB masters and reusable for various AMBA-based SOC designs. The keys to the scalability and the reusability are Object-Oriented Programming (OOP), virtual port, and bind operation. This paper describes how OOP, virtual port, and bind features are used to implement AHB protocol checker. Using the AHB protocol checker, an AHB simulation monitor is constructed. The monitor checks the legal bus arbitration and detects the first cycle of an AHB transaction. Then it calls AHB protocol checker to check the expected AHB signal sequences. We integrate the AHB bus monitor into Verilog simulation environment to replace time-consuming visual waveform inspection, and it allows us to find design bugs quickly. This paper also discusses AMBA AHB bus transaction coverage metrics and AHB transaction coverage analysis. Test programs for five AHB masters of an SOC, four channel DMAs and a host interface unit are executed and transaction coverage for DMA verification is collected during simulation. These coverage results can be used to determine the weak point of test programs in terms of the number of bus transactions occurred and guide to improve the quality of the test programs. Also, the coverage results can be used to obtain bus utilization statistics since the bus cycles occupied by each AHB master can be obtained.

• 한국전자통신학회논문지
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• 제9권12호
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• pp.1365-1372
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• 2014

최근 LTE(Long-Term Evolution) 이동통신시스템이 보급되어 본격적인 서비스가 제공되고 있다. 특히 LTE 시스템은 3G 시스템 등 과거 이동통신시스템 대비 월등한 전송 속도를 보장함으로써 높은 전송 속도를 요구하는 서비스도 이동단말을 통해서 제공될 수 있도록 하고 있다. 향후 IPTV와 같은 멀티미디어 서비스가 LTE 시스템을 통해서 제공되기 위해서는 실제 사용 환경에서 LTE 시스템이 보여주는 전송 속도의 변화에 대한 기본적인 이해가 필요하다. 따라서 본 논문에서는 CQI와 BLER과 같은 무선 품질 지표가 LTE 시스템의 전송 속도에 영향을 미치는 체제에 대해서 살펴보고 실측 결과를 통해서 이를 검증한다.

• 한국의류산업학회지
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• 제18권1호
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• pp.48-62
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• 2016

Consumers have come to demand high quality, affordable prices, and innovative product designs of the outdoor wear market due to their well-being and leisure oriented lifestyle. A new system of business in outdoor wear has emerged in the process through which corporations have endeavored to satisfy such consumer needs. Outdoor wear brands have utilized social network services (SNS) such as Facebook and Twitter as means of marketing and have built close relations with consumers based on communication through these media. Recently, explosively escalating SNS data are referred to as social big data, and now that every consumer online is a commentator, reviewer, and publisher, the outdoor wear market and all of its brands have to stop talking and start listening to how they are perceived. Therefore, this study employs Social $Metrics^{TM}$, a social big data analysis solution by Daumsoft, Inc., to verify changes in the allusions related to outdoor wear market found on SNS. This study aims to identify changes in consumer perceptions of outdoor wear based on changes in outdoor wear search words and trends in positive and negative public opinion found in SNS social big data. In addition, products of interest, the major brands mentioned, the attributes taken into consideration during purchases of products, and consumers' psychology were categorized and analyzed by means of keywords related to outdoor wear brands found on SNS. The results of this study will provide fundamental resources for outdoor wear brands' market entry and brand strategy implementation in the future.

• Investigative Magnetic Resonance Imaging
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• 제21권4호
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• pp.223-232
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• 2017

Purpose: To report the use of multiband accelerated echo-planar imaging (EPI) for resting-state functional MRI (rs-fMRI) to achieve rapid high temporal resolution at 3T compared to conventional EPI. Materials and Methods: rs-fMRI data were acquired from 20 healthy right-handed volunteers by using three methods: conventional single-band gradient-echo EPI acquisition (Data 1), multiband gradient-echo EPI acquisition with 240 volumes (Data 2) and 480 volumes (Data 3). Temporal signal-to-noise ratio (tSNR) maps were obtained by dividing the mean of the time course of each voxel by its temporal standard deviation. The resting-state sensorimotor network (SMN) and default mode network (DMN) were estimated using independent component analysis (ICA) and a seed-based method. One-way analysis of variance (ANOVA) was performed between the tSNR map, SMN, and DMN from the three data sets for between-group analysis. P < 0.05 with a family-wise error (FWE) correction for multiple comparisons was considered statistically significant. Results: One-way ANOVA and post-hoc two-sample t-tests showed that the tSNR was higher in Data 1 than Data 2 and 3 in white matter structures such as the striatum and medial and superior longitudinal fasciculus. One-way ANOVA revealed no differences in SMN or DMN across the three data sets. Conclusion: Within the adapted metrics estimated under specific imaging conditions employed in this study, multiband accelerated EPI, which substantially reduced scan times, provides the same quality image of functional connectivity as rs-fMRI by using conventional EPI at 3T. Under employed imaging conditions, this technique shows strong potential for clinical acceptance and translation of rs-fMRI protocols with potential advantages in spatial and/or temporal resolution. However, further study is warranted to evaluate whether the current findings can be generalized in diverse settings.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권3호
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• pp.1168-1188
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• 2018

Social Network Aggregators are used to maintain and manage manifold accounts over multiple online social networks. Displaying the Activity feed for each social network on a common dashboard has been the status quo of social aggregators for long, however retrieving the desired data from various social networks is a major concern. A user inputs the query desiring the specific outcome from the social networks. Since the intention of the query is solely known by user, therefore the output of the query may not be as per user's expectation unless the system considers 'user-centric' factors. Moreover, the quality of solution depends on these user-centric factors, the user inclination and the nature of the network as well. Thus, there is a need for a system that understands the user's intent serving structured objects. Further, choosing the best execution and optimal ranking functions is also a high priority concern. The current work finds motivation from the above requirements and thus proposes the design of a query processing system to retrieve information from social network that extracts user's intent from various social networks. For further improvements in the research the machine learning techniques are incorporated such as Latent Dirichlet Algorithm (LDA) and Ranking Algorithm to improve the query results and fetch the information using data mining techniques.The proposed framework uniquely contributes a user-centric query retrieval model based on natural language and it is worth mentioning that the proposed framework is efficient when compared on temporal metrics. The proposed Query Processing System to Retrieve Information from Social Network (QPSSN) will increase the discoverability of the user, helps the businesses to collaboratively execute promotions, determine new networks and people. It is an innovative approach to investigate the new aspects of social network. The proposed model offers a significant breakthrough scoring up to precision and recall respectively.