• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.8-16
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• 2007

For the improvement of coding efficiency, the H.264/AVC video coding standard employs new coding tools compared with existing coding standards. However, due to these new coding tools, the complexity of K264/AVC standard encoder is greatly increased. Specifically, the inter/intra mode decision method using RDO(rate-distortion optimization) technique is one of the most complex parts in H.264/AVC. In this paper, we focus on the complexity reduction in macroblock mode decision. In the proposed method, we reduce the complexity of the $4{\times}4$ mode decision process using $4{\times}4$ simple square filters, and using spatial block correlation method. Additionally, exploiting the best mode of sub_macroblock in $Inter8{\times}8$ mode, we proposed an algorithm to eliminate some intra modes in current macroblock mode decision process. In addition, we employed a method to raise the probability to select SKIP, $Intra16{\times}16$, and $Intra16{\times}16$ modes which usually show low complexity and low bitrate compared with other modes. From the simulation results, the proposed algorithm reduce the encoding time by maximum 83% of total, and reduce the bitrate of the overall sequences by $8{\sim}10%$ on the average compared with existing coding methods.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.19-30
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• 2012

For digital data compression, the quantization is the main part of the lossy source coding. In order to improve the performance of quantization, the vector quantizer(VQ) can be employed. The encoding complexity, however, exponentially increases as the vector dimension or bit rate gets large. Much research has been conducted to alleviate such problems of VQ. Especially for high bit rates, a constrained VQ, which is called the sample-adaptive product quantizer(SAPQ), has been proposed for reducing the hugh encoding complexity of regular VQs. SAPQ has very similar structure as to the product VQ(PQ). However, the quantizer performance can be better than the PQ case. Further, the encoding complexity and the memory requirement for the codebooks are lower than the regular full-search VQ case. Among SAPQs, 1-SAPQ has a simple quantizer structure, where each product codebook is symmetric with respect to the diagonal line in the underlying vector space. It is known that 1-SAPQ shows a good performance for i.i.d. sources. In this paper, a study on designing 1-SAPQ for the first-order Markov process. For an efficient design of 1-SAPQ, an algorithm for the initial codebook is proposed, and through the numerical analysis it is shown that 1-SAPQ shows better quantizer distortion than the VQ case, of which encoding complexity is similar to that of 1-SAPQ, and shows distortions, which are close to that of the DPCM(differential pulse coded modulation) scheme with the Lloyd-Max quantizer.

• Journal of Broadcast Engineering
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• v.17 no.1
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• pp.108-121
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• 2012

As Scalable Video Coding (SVC) is a video compression standard extended from H.264/AVC, it is a way to provide scalability in terms of temporal, spatial and quality. Although the compression efficiency of SVC is increased due to the scalability in many aspect, it is essential to reduce the complexity in order to efficiently use because the complexity is relatively increased. To reduce the complexity of SVC in the paper, we propose fast mode decision algorithm to reduce the complexity of encoding process using direction information of B-picture by efficiently performing inter-layer prediction. The proposed algorithm is a fast mode decision algorithm that makes different from detection mode number of forward and backward, bi-direction in the way using best mode of base-layer up-sampled after simply SKIP mode detection using the direction information of best mode of base-layer up-sampled. The experimental results show that the proposed algorithm approach can achieve the maximum computational time saving about 53% with almost no loss of rate distortion (RD) performance in the enhancement layer.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.3
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• pp.459-475
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• 2008

This study analyzes the network structure of the Metropolitan Seoul subway system by applying complex network analysis methods. For the purpose, we construct the Metropolitan Seoul subway system as a network graph, and then calculate various indices introduced in complex network analysis. Structural characteristics of Metropolitan Seoul subway network are discussed by these indices. In particular, this study determines the shortest paths between nodes based on the weighted distance (physical and time distance) as well as topological network distance, since urban travel movements are more sensitive for them. We introduce an accessibility measurement based on the shortest distance both in terms of physical distance and network distance, and then compare the spatial structure between two. Accessibility levels of the system have been getting up overall, and thus the accessibility gaps have been getting lessen between center located subway stops and remote ones during the last 10 years. Passenger traffic volumes are explored from real passenger transaction databases by utilizing data mining techniques, and mapped by GIS. Clear differences reveal between the spatial patterns of real passenger flows and accessibility. That is, passenger flows of the Metropolitan Seoul subway system are related with population distribution and land use around subway stops as well as the accessibility supported by the subway network.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.1
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• pp.701-711
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• 2009

The inner space of building is increasingly becoming complex as urban activities increase in variety, and the actual space size also increases. This trend necessitate the utilization of three dimensional position information within the inner space of buildings. Standard GIS web service technology and visualization technology are applied to 3D inner space building data to share these information for better decision making in building related applications such as fire evacuation, facilities management and market analysis. This study aims to effectively model and visualize the three dimensional space of building interiors in the GIS aspect, and to be able to share the information through standard GIS web service. The various elements of inner model was assigned and stored into pre-designed spatial database tables respectively. GIS web server was then configured to service the database which was populated with 3D inner model data. On the client side, 3D visualization modules was developed using a 3D graphic rendering S/W engine.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.3
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• pp.83-90
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• 2010

In modern society, there has been an increase in needs to protect the life and property of the people, because the number of various crimes is on the increase due to the sudden and complicated changes of the urban environment. For the needs, security persons in the urban area are expanding the role and skill of police for more effective crime prevention and surveillance, although the number of policeman/woman is insufficient and their tasks are hard. Recently, a system to observe and prevent crime in effective has been introduced by using such an artificial surveillance device as CCTV to monitor focusing on one area for 24 hours. However, the system brings such problems as the insufficiency of systematic criteria to install surveillance device and the invasion of privacy. Therefore, in this study, artificial surveillance zones to monitor crimes are selected by applying spatial features between artificial surveillance devices including CCTV and crime occurrence place, and using GIS spatial analysis techniques. As a result of selecting, it's found that the number of CCTV is absolutely insufficient and spatial distribution is not fully considered in the existing location of installed CCTV.

• Journal of KIISE:Software and Applications
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• v.26 no.9
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• pp.1039-1051
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• 1999

시공간 데이타베이스는 현실세계의 객체에 대하여 효율적인 공간 관리와 이력 관리를 지원한다. 이러한 시공간 데이타베이스는 시간차원과 공간차원이라는 이질적 데이타 공간을 관리하여야 하는 대단히 복잡한 시스템이다. 따라서 데이타에 대한 효율적 접근 방법에 대한 연구가 필수적이며, 이는 효율적 색인 기법의 개발을 통하여 이룰 수 있다. 그러나 시공간 데이타에 대한 접근방법 연구는 거의 이루어지지 않고 있으며 극소수의 사례들마저도 공간 객체의 이력 개념을 지원하는 것이 아니라 멀티미디어 객체의 상대적 시간만을 지원하고 있다. 따라서 이 논문에서는 공간 데이타의 이력을 표현하는 시공간 데이타에 대하여 효율적으로 색인하기 위한 방안으로서 시간과 공간을 단일화된 색인 영역으로 통합하는 단일화된 시공간 색인 모델을 제시하고, 이를 기존의 R-트리를 기반으로 확장한 색인을 설계 및 구현하였으며, 아울러 다양한 유형의 시공간 연산에 대한 색인의 성능을 평가하였다.Abstract Spatiotemporal databases are able to support an efficient spatial management as well as historical management for an object in the real world. It is very complex to manage these two dimensions why there exists on difference of inborn property of temporal and spatial dimensions. Therefore an efficient access method should be studied, and it can be done by means of development of efficient indexing technology.However, there is a few related work in the research of access methods of spatiotemporal data. Also the previous works do not support the concept of history for spatial object, and only support the relative time among multimedia objects. Therefore, in this paper, we propose a unified Spatiotemporal index model as an efficient index for Spatiotemporal data. And we not only design Spatiotemporal index that has been extended to historical management facility on the basis of conventional R-tree, but also implement it. Finally we have evaluated performance of index for the various kinds of Spatiotemporal operations.

• Journal of Intelligence and Information Systems
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• v.10 no.1
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• pp.93-107
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• 2004

This study is concerned with proposing a new construct named "spatial metaphor" in the field of user interface design for web. Recently, web has been recognized as an important vehicle of delivering messages and information to customers. Since both hyperlink and multimedia technology are crucial part of web, its user interface requires a new approach to enhance user's acceptance of web. In this sense, we introduced a new concept named "spatial metaphor" instead of hierarchical menus. As a theoretical basis, Davis (1986)'s TAM(Technology Acceptance Model) was used to test the statistical validity of the proposed spatial metaphor. For test web site, we developed a prototype designed by using atomic-web system and spatial metaphor. By using the prototype, we built a web-based questionnaire system so that respondents can use it directly before answering the questionnaire. To prove its statistical validity, we collected valid questionnaires and tested with LISREL. In this way, statistical validity of our proposed approach was proven.approach was proven.

• Spatial Information Research
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• v.14 no.4 s.39
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• pp.379-389
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• 2006

Map databases for CNS (Car Navigation System) can be accessed quickly and compressed efficiently due to that these are usually recorded as in a PSF (Physical Storage Format). However, it is difficult to create and manage data storage based on a file-system. To solve these problems, DBMS needs to be combined with spatial data management. Therefore, we developed an embedded DBMS with which to store data and conduct quick searches in CNS. Spatial data could be easily managed and accessed using the compression method, Multi-Link, spatial index, and spatial division. In the result, the proposed embedded DBMS searched quickly and stably supported data management. If synchronization is applied in DBMS, it is expected to utilize the advantages of an embedded DBMS.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.4
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• pp.350-369
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• 2018

The aim of this study is to investigate foreigner's spatial change and relations to industrial workers in the sixteen districts of Busan metropolitan city from 2000 year to 2015 year. To achieve the goal, the data published in Pusan Statistical Yearbook was analyzed by descriptive and inferential statistics. The results are summarized in the followings. Firstly, the spatial changes of foreigners as a whole during 2000~2015 year are different based on their nationality. Secondly, foreigner's spatial change based on nationality and gender is much complex. The meaning of foreigner's spatial change in each district tested by nonparametric statistics is different according to a time scale. Thirdly, the relationality between foreigners as a whole and industrial workers in the sixteen districts is different by nationality and gender. The study method can be utilized at other cities or regions, and the results of those studies can be helpful to solve various problems due to increasing foreigners.