• 대한기계학회논문집A
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• 제31권6호
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• pp.694-700
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• 2007

Recently, a new cellular metal, WBK(Wire woven Bulk Kagome) has been introduced. WBK is fabricated by assembling metal wires in six directions into a Kagome-like truss structure and by brazing it at all the crossings. Wires as the raw material are easy to handle and to attain high strength with minimum defect. And the strength and energy absorption are superior to previous cellular metals. Therefore, WBK seems to be promising once the fabrication process for mass production is developed. In this paper, an upper bound solution for the mechanical properties of the bulk WBK under compression is presented. In order to simulate uniform behavior of WBK consisted of perfectly uniform cells, a unit cell of WBK with periodic boundary conditions is analyzed by the finite element method. In comparison with experimental test results, it is found that the solution provides a good approximation of the mechanical properties of bulk WBK cellular metals except for Young's modulus. And also, the brazing joint size does not have any significant effect on the properties with an exception of an idealized thin joint.

• 대한안전경영과학회지
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• 제17권2호
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• pp.89-96
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• 2015

The weapon systems development has some distinct characteristics in that a big size of government budget (derived from national tax) has been expended frequently and the completion of the development projects seems to take long. Thus, the impact of the potential changes in the required operational capability on the development activities can induce some type of project risks. As such, proper management of project risk has been one of crucial subjects in the weapon systems development. Although a variety of methods can be considered, an approach based on the test and evaluation (T&E) process has been selected in this paper in order to appropriately handle those potential risks. In the study of the underlying T&E process, the safety consideration (for instance, explosiveness) of weapon systems is also included. To achieve the objective of the paper, a step-by-step procedure is first presented in the analysis of the T&E process. Then, to pursue some enhancement on the process, a set of necessary and useful activities are added in terms of risk and safety management. The resultant process is further analyzed and tailored based on a design structure matrix method. The case study of a tank development is also discussed.

• 제어로봇시스템학회논문지
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• 제15권9호
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• pp.946-951
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• 2009

The small multi-jointed robots for most education are developed with the way of firmware. But the firmware may be very difficult to develop as gradually increasing throughputs and control routines. Due to limit of firmware we try to use on RTOS, but hard to adapt on the small multi-jointed robots. It would be hard to install RTOS into the small multi-jointed robots because of the size capacity of RTOS, and lack of libraries for control of the particular hardware. Moreover, even its RTOS with many functions causes its to make overheads scheduling, TCB (Task Control Block), and task states. Also to keep maintenance of RTOS, it is composed of components for the whole structure of my proposed RTOS. Additionally, We provided with libraries of servo motor and sensor control and developed RMS (Rate Montonic scheduler) to handle tasks on real time and reduce overheads. Therefore, It is possible to work the fixed priority and task preemptive way. We show one example of the multi-jointed robot installed with my proposed RTOS, which shows to obstacle avoidance and climbing up the slope.

• 대한전자공학회논문지
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• 제22권6호
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• pp.58-62
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• 1985

이온 주입된 소형 MOSFET소자에 대한 해석적 문턱 전압 모델이 유도되었다. 일정한 도우핑 농도를 갖는 MOSFET에 적용되는 Yau 모델을 implanted channel구조와 bird's beat구조의 MOSFET에 대하여 적합한 형태로 수정하여 short channel 현상과 narrow width 현상을 정량적으로 설명하였다. Channel영역의 불순물 분포를 SUPREM 결과에서 2-step profile로 근사시켜 문턱 전압의 short channel model을 제안하였다. Weighting factor를 사용하여 bird's beat 영역의 불순물 분포를 고려함으로써 narrow width 현상을 성공적으로 설명하였다.

• 한국정보시스템학회지:정보시스템연구
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• 제8권1호
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• pp.5-26
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• 1999

In recent years there has been an increasing amount of attention paid to outosourcing of information systems (IS) functions in organizations. The changing and more strategic role of outsourcing in business firms has been given much coverage in academic and trade publications. Trying to remain competitive and up-to-date in the rapidly developing world of computer technology is becoming a financial burden to many organizations in fields such as banking and financial services, health care, and manufacturing. Hiring outsiders to handle part or even all of its information services helps an organization provide better services and maintain a competitive advantage. This paper attempts to provide a benchmark of current IS outsourcing utilization in Korea. A detailed descriptive analysis of survey responses from 78 Korean companies indicates the usage, length of experience, expenditure of outsourcing, and kinds of IS functions being outsourced. The study also analyzes the effects (strategic, economic, and technological) of IS outsourcing with respect to the length of experience, expenditure of outsourcing, and kinds of IS functions being outsourced As a result of the analysis there are significant differences in the strategic, economic and technological effects of IS outsourcing with respect to the expenditure of outsourcing, kinds of IS functions being outsourced and firm size.

• 대한산업공학회지
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• 제25권2호
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• pp.233-239
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• 1999

With the increase of Internet protocol (IP) packets the performance of routers became an important issue in internetworking. In this paper we examined the matching algorithm in gigabit router which has input queue with virtual output queueing. Port partitioning concept is employed to reduce the computational burden of the scheduler within a switch. The input and output ports are divided into two groups such that the matching algorithm is implemented within each input-output pair group in parallel. The matching is performed by exchanging input and output port groups at every time slot to handle all incoming traffics. Two algorithms, maximal weight matching by port partitioning (MPP) and modified maximal weight matching by port partitioning (MMPP) are presented. MMPP has the lowest delay for every packet arrival rate. The buffer size on a port is approximately 20-60 packets depending on the packet arrival rates. The throughput is illustrated to be linear to the packet arrival rate, which can be achieved under highly efficient matching algorithm.

• Journal of Electrical Engineering and Technology
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• 제8권4호
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• pp.879-888
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• 2013

This paper addresses the vision based local path planning system for obstacle avoidance. To handle the obstacles which exist beyond the field of view (FOV), we propose a Panoramic Environment Map (PEM) using the MDGHM-SIFT algorithm. Moreover, we propose a Complexity Measure (CM) and Fuzzy logic-based Avoidance Motion Selection (FAMS) system to enable a humanoid robot to automatically decide its own direction and walking motion when avoiding an obstacle. The CM provides automation in deciding the direction of avoidance, whereas the FAMS system chooses the avoidance path and walking motion, based on environment conditions such as the size of the obstacle and the available space around it. The proposed system was applied to a humanoid robot that we designed. The results of the experiment show that the proposed method can be effectively applied to decide the avoidance direction and the walking motion of a humanoid robot.

• Journal of Information Processing Systems
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• 제4권1호
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• pp.9-16
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• 2008

This paper describes the design and implementation of a two-tier DBMS for handling massive data and providing faster response time. In the present day, the main requirements of DBMS are figured out using two aspects. The first is handling large amounts of data. And the second is providing fast response time. But in fact, Traditional DBMS cannot fulfill both the requirements. The disk-oriented DBMS can handle massive data but the response time is relatively slower than the memory-resident DBMS. On the other hand, the memory-resident DBMS can provide fast response time but they have original restrictions of database size. In this paper, to meet the requirements of handling large volumes of data and providing fast response time, a two-tier DBMS is proposed. The cold-data which does not require fast response times are managed by disk storage manager, and the hot-data which require fast response time among the large volumes of data are handled by memory storage manager as snapshots. As a result, the proposed system performs significantly better than disk-oriented DBMS with an added advantage to manage massive data at the same time.

• International Journal of Knowledge Content Development & Technology
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• 제11권2호
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• pp.37-54
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• 2021

The study determined the access, skills and constraints towards the usage of ICT among barangay officials. A complete enumeration technique was used due to the small size of the population. A total of 121 barangay secretaries and barangay treasurers comprised the study respondents. The findings revealed that most of barangay officials have access to personal computer at home and in the office using their own mobile data and office internet connectivity. With the support from the Local Government Unit (LGU), it was found that most of the respondents are advance and proficient in computer usage. As constraints to ICT usage, the study respondents still experienced slow internet bandwidth that makes connection and communication weak along with the low income status. Consequently, it was found that there were no significant differences in terms of skills and constraints among barangay secretaries and barangay treasurers towards using ICT. It can be concluded that study respondents prefer to use office computer to access the information they need due to the convenience and availability of resources. The study respondents were competent enough to handle their job well but listed slow internet and low financial resources may hamper their ICT usage. Research implications were also offered.

• 대한임베디드공학회논문지
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• 제16권4호
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• pp.153-161
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• 2021

Real-time access is required to handle continuous and unstructured data and should be flexible in management under dynamic state. Platform can be built to allow data collection, storage, and processing from local-server or multi-server. Although the former centralize method is easy to control, it creates an overload problem because it proceeds all the processing in one unit, and the latter distributed method performs parallel processing, so it is fast to respond and can easily scale system capacity, but the design is complex. This paper provides data collection and processing on one platform to derive significant insights from various data held by an enterprise or agency in the latter manner, which is intuitively available on dashboards and utilizes Spark to improve distributed processing performance. All service utilize dockers to distribute and management. The data used in this study was 100% collected from Kafka, showing that when the file size is 4.4 gigabytes, the data processing speed in spark cluster mode is 2 minute 15 seconds, about 3 minutes 19 seconds faster than the local mode.