• Title/Summary/Keyword: Dynamic focusing

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Real-Time 3D Ultrasound Imaging Method Using a Cross Array Based on Synthetic Aperture Focusing: I. Spherical Wave Transmission Approach (합성구경 기반의 교차어레이를 이용한 실시간 3차원 초음파 영상화 기법 : I. 구형파 송신 방법)

  • 김강식;송태경
    • Journal of Biomedical Engineering Research
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    • v.25 no.5
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    • pp.391-401
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    • 2004
  • 3D imaging systems using 2D phased arrays have a large number of active channels, compelling to use a very expensive and bulky beamforming hardware, and suffer from low volume rate because, in principle, at least one ultrasound transmit-receive event is necessary to construct each scanline. A high speed 3D imaging method using a cross array proposed previously to solve the above limitations can implement fast scanning and dynamic focusing in the lateral direction but suffer from low resolution except at the fixed transmit focusing along the elevational direction. To overcome these limitations, we propose a new real-time volumetric imaging method using a cross array based on the synthetic aperture technique. In the proposed method, ultrasound wave is transmitted successively using each elements of an 1D transmit array transducer, one at a time, which is placed along the elevational direction and for each firing, the returning pulse echoes are received using all elements of an 1D receive array transducer placed along the lateral direction. On receive, by employing the conventional dynamic focusing and synthetic aperture method along lateral and elevational directions, respectively, ultrasound waves can be focused effectively at all imaging points. In addition, in the proposed method, a volume of interest consisting of any required number of slice images, can be constructed with the same number of transmit-receive steps as the total number of transmit array elements. Computer simulation results show that the proposed method can provide the same and greatly improved resolutions in the lateral and elevational directions, respectively, compared with the 3D imaging method using a cross array based on the conventional fixed focusing. In the accompanying paper, we will also propose a new real-time 3D imaging method using a cross array for improving transmit power and elevational spatial resolution, which uses linear wave fronts on transmit.

Dynamic Virtual Ontology using Tags with Semantic Relationship on Social-web to Support Effective Search (효율적 자원 탐색을 위한 소셜 웹 태그들을 이용한 동적 가상 온톨로지 생성 연구)

  • Lee, Hyun Jung;Sohn, Mye
    • Journal of Intelligence and Information Systems
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    • v.19 no.1
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    • pp.19-33
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    • 2013
  • In this research, a proposed Dynamic Virtual Ontology using Tags (DyVOT) supports dynamic search of resources depending on user's requirements using tags from social web driven resources. It is general that the tags are defined by annotations of a series of described words by social users who usually tags social information resources such as web-page, images, u-tube, videos, etc. Therefore, tags are characterized and mirrored by information resources. Therefore, it is possible for tags as meta-data to match into some resources. Consequently, we can extract semantic relationships between tags owing to the dependency of relationships between tags as representatives of resources. However, to do this, there is limitation because there are allophonic synonym and homonym among tags that are usually marked by a series of words. Thus, research related to folksonomies using tags have been applied to classification of words by semantic-based allophonic synonym. In addition, some research are focusing on clustering and/or classification of resources by semantic-based relationships among tags. In spite of, there also is limitation of these research because these are focusing on semantic-based hyper/hypo relationships or clustering among tags without consideration of conceptual associative relationships between classified or clustered groups. It makes difficulty to effective searching resources depending on user requirements. In this research, the proposed DyVOT uses tags and constructs ontologyfor effective search. We assumed that tags are extracted from user requirements, which are used to construct multi sub-ontology as combinations of tags that are composed of a part of the tags or all. In addition, the proposed DyVOT constructs ontology which is based on hierarchical and associative relationships among tags for effective search of a solution. The ontology is composed of static- and dynamic-ontology. The static-ontology defines semantic-based hierarchical hyper/hypo relationships among tags as in (http://semanticcloud.sandra-siegel.de/) with a tree structure. From the static-ontology, the DyVOT extracts multi sub-ontology using multi sub-tag which are constructed by parts of tags. Finally, sub-ontology are constructed by hierarchy paths which contain the sub-tag. To create dynamic-ontology by the proposed DyVOT, it is necessary to define associative relationships among multi sub-ontology that are extracted from hierarchical relationships of static-ontology. The associative relationship is defined by shared resources between tags which are linked by multi sub-ontology. The association is measured by the degree of shared resources that are allocated into the tags of sub-ontology. If the value of association is larger than threshold value, then associative relationship among tags is newly created. The associative relationships are used to merge and construct new hierarchy the multi sub-ontology. To construct dynamic-ontology, it is essential to defined new class which is linked by two more sub-ontology, which is generated by merged tags which are highly associative by proving using shared resources. Thereby, the class is applied to generate new hierarchy with extracted multi sub-ontology to create a dynamic-ontology. The new class is settle down on the ontology. So, the newly created class needs to be belong to the dynamic-ontology. So, the class used to new hyper/hypo hierarchy relationship between the class and tags which are linked to multi sub-ontology. At last, DyVOT is developed by newly defined associative relationships which are extracted from hierarchical relationships among tags. Resources are matched into the DyVOT which narrows down search boundary and shrinks the search paths. Finally, we can create the DyVOT using the newly defined associative relationships. While static data catalog (Dean and Ghemawat, 2004; 2008) statically searches resources depending on user requirements, the proposed DyVOT dynamically searches resources using multi sub-ontology by parallel processing. In this light, the DyVOT supports improvement of correctness and agility of search and decreasing of search effort by reduction of search path.

Korea's Limit to Growth from Circular Causation Perspective: Focusing on Crisis Factors, Population, Economy, Resources, Environment, and Food (인과지도로 본 한국의 성장의 한계: 인구, 경제, 자원, 환경, 식량 위기요인을 중심으로)

  • Moon, Tae-Hoon;Kim, Byung-Suk
    • Korean System Dynamics Review
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    • v.10 no.3
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    • pp.47-79
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    • 2009
  • The paper examines dynamic relationship among 'Limit to Growth' factors in Korea using causal loop diagram. It also aims to explore policy implications for Korea in overcoming current difficulties and future crisis we may face. For this purpose, five factors -economy, population, resource, environment, food- used in the were adopted as an analytical framework. Findings show that Korea is fragile to external shock such as world economic crisis, food price surge, and resource price -including energy price- hike. High dependency of energy, food and resource on foreign market was found to be a major source of limit to growth in Korea. Furthermore, environmental problems like global warming could be a major external shock that could hit Korea harder than the rest of the world. Policy implications and measures for these problems were discussed too.

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A Study on the Automatic Parallelization Method and Tool Development

  • Shin, Woochang
    • International Journal of Internet, Broadcasting and Communication
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    • v.12 no.3
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    • pp.87-94
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    • 2020
  • Recently, computer hardware is evolving toward increasing the number of computing cores, not increasing the clock speed. In order to use the performance of parallelized hardware to the maximum, the running program must also be parallelized. However, software developers are accustomed to sequential programs, and in most cases, write programs that operate sequentially. They also have a lot of difficulty designing and developing software in parallel. We propose a method to automatically convert a sequential C/C++ program into a parallelized program, and develop a parallelization tool that supports it. It supports open multiprocessing (OpenMP) and parallel patterns library (PPL) as a parallel framework. Perfect automatic parallelization is difficult due to dynamic features such as pointer operation and polymorphism in C/C++ language. This study focuses on verifying the conditions of parallelization rather than focusing on fully automatic parallelization, and providing advice to developers in detail if parallelization is not possible.

Performance Effect of the Fits between Industrial Environment, Innovation Capacity and Innovation: Focusing on Innovation-Intensive Korean Firms

  • Lee, Seung-Hyun;Park, Young-Il;Kwon, Youngkwan
    • Asian Journal of Innovation and Policy
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    • v.4 no.3
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    • pp.328-359
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    • 2015
  • To explain the performance gap between firms in the same industry, this study focuses on innovation. It provides a new framework using the dynamic-capability view based on empirical analysis of domestic businesses. The findings of this study are as follows: First, when the uncertainty and competition intensity in the business environment and the level of innovation have “fit”, it means that when the former goes up, so does the latter. In this regard, when the innovation capability of a firm is high, being “fit” means that the level of innovation is also high. When there was fitting innovation on industrial environment and innovation capacity, companies were able to achieve relatively high performance. Also, it was confirmed that instead of innovation for innovation capacity, innovation for industrial environment led to relatively higher performances of firms.

How to Manage Business Process as Knowledge Assets based on Ontological Approach: Focusing on Sales Order Process

  • Joo, Jae-Woo;Kim, Gun-Woo;Morin, Jean-Henry
    • 한국경영정보학회:학술대회논문집
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    • 2008.06a
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    • pp.264-269
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    • 2008
  • Considering our increasingly interconnected organizations heavily relying on business processes and the growing need for timely accurate knowledge to achieve greater agility in the enterprise, the idea of looking at business processes as a knowledge object is gaining momentum. Business process information is knowledge and should consequently be managed as a valuable organizational asset, particularly because organizations need to react in near real time to environmental changes and events. This paper provides an overview of the situation in this field arguing for a better definition of the intersections between knowledge and business process management. When business process is seen as knowledge, it should be managed as such. We assess and discuss some of the resulting benefits and considering the need for greater dynamic integration between the two domains, we look at ontologies as an interesting technical approach to bridging this gap showing an example for an ontology based sales order process.

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A Study on the Calculation of Optimal Subsidy for LED Appliance using Diffusion Model (확산모형을 이용한 LED 조명기기의 최적보조금 산정에 관한 연구)

  • Son, Hag-Sig
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.3
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    • pp.1-7
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    • 2015
  • Korea's electricity supply and demand policy has focusing on electricity demand side management instead of the expanding supply and a lot of effort for LED(Light Emitting Diode) at the time. This paper calculated the optimal subsidy for LED spread. For this purpose, it analyzed the impact on spread of the lighting appliances each subsidy level from BDM(Bass Diffusion Model) and predicted the number of lighting appliances according to subsidy level in the future. The case study is calculated susidy for satisfaction of LED target using the suggested model in the future and verified availability.

Design and Analysis of A Mini Linear Optical Pickup Actuator

  • Park, Joon-Hyuk;Baek, Yoon-Su;Park, Young-Pil
    • Journal of Mechanical Science and Technology
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    • v.17 no.11
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    • pp.1616-1627
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    • 2003
  • This paper describes a mini linear optical pickup actuator. To reduce the size, inner yokes are designed to guide the mover and outer yokes of permanent magnets are removed. Magnetic circuit method is used to determine the thrust force. Virtual path method is proposed to analyze the open magnetic circuit analysis. The magnetic circuit of the proposed actuator can be a closed circuit due to the virtual path model of the outer magnetic flux. The validity of virtual path method is evaluated by comparing to the FEM analysis. Structural vibration is investigated using FEM and the design of the mover is modified to improve the vibration characteristic. Dynamic characteristic experiments shows that the performance of the proposed actuator is enough to be used as a coarse and fine seeking actuator simultaneously and the thrust force margin for loading a focusing actuator is guaranteed.

Actuating Characteristics of an Asymmetric Optical Pick-up Fine Actuator of a High Speed CD-ROM (고배속 CD-ROM용 비대칭형 광픽업 미세구동기의 구동특성)

  • 고상선;류제하;박기환;정호섭
    • Journal of KSNVE
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    • v.8 no.2
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    • pp.346-352
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    • 1998
  • This paper presents actuating characteristics of an asymmetric high-speed optical pick-up fine actuator that can be installed in a small area such as a notebook personal computer. In the asymmetric actuator four points (mass center, actuation center, supporting point of wire suspension on a bobbin, and optical axis) are not coincident so that the proposed actuator suspension reveals undesirable suspension resonance in the pitch and yaw direction. Lumped parameter dynamic model in each direction is used to investigate the driving characteristics with respect to relative location of the four points. Some of desired design directions toward reducing resonance peaks are suggested by using sensitivity information. In order to avoid undesirable resonance, at least supporting point on the obbin must be located in the middle of the mass and actuation center of the asymmetric pick-up actuator.

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An Analysis of Exhibition Video Contents in International Trade Show-Focused on the ISE 2013 (국제 무역박람회의 전시영상콘텐츠 분석 -ISE 2013을 중심으로)

  • Yang, Y.E.
    • Journal of Korea Multimedia Society
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    • v.17 no.7
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    • pp.895-905
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    • 2014
  • Recently the trade show is a massive marketing effort of a particular industry and introduces new products to potential customers, as well as the ability to elevate the brand's image and corporate identity. It is increasing its importance as a venue of communication. In these changes, the exhibition is required to have the emotional approach to enhance the dynamic and creative image of companies. Therefore, the product itself as well as the importance of various visual contents of the exhibition is increasing positive effect of the image and marketing on their products. In this sense, this study analyzes video contents of the exhibition that was held in Amsterdam, the Netherlands, Europe's largest display show 'ISE (Integrated Systems Europe)' in 2013, focusing on the domestic company, Samsung, LG Electronics and other four foreign companies. The analysis is based on the Herbert Zettl's applied media aesthetics related to the video contents, through which we can find the way to the development of exhibition video contents making for Trade show.