• 제목/요약/키워드: on-line design

검색결과 4,951건 처리시간 0.033초

High Bit-Rates Quantization of the First-Order Markov Process Based on a Codebook-Constrained Sample-Adaptive Product Quantizers (부호책 제한을 가지는 표본 적응 프로덕트 양자기를 이용한 1차 마르코프 과정의 고 전송률 양자화)

  • Kim, Dong-Sik
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • 제49권1호
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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.

An Improved Monte-Carlo Simulation Method for Typhoon Risk Assessment in Korea (개선(改善)된 Monte-Carlo 시뮬레이션 방법(方法)에 의한 한국(韓國)의 태풍위험도(颱風危險度) 분석(分析))

  • Cho, Hyo Nam;Chang, Dong Il;Cha, Cheol Jun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제7권4호
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    • pp.159-165
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    • 1987
  • This study proposes an operational method of typhoon risk assessments in Korea, using Statistical analysis and probabilistic description of typhoon at a site. Two alternative simulation and fitting methods are discussed to predict the probabilistic typhoon wind speeds by indirect methods. A Commonly used indirect method is Russell's procedure, which generates about 1,000 Simulation data for typhoon winds, statistically evaluate the base-line distribution, and then fits the results to the Weibull distribution based on probabilistic description of climatological Characteristics and Wind field model of typhoon at a site. However, an alternative procedure proposed in this Paper simulates extreme typhoon wind data of about 150~200 years and directly fits the generated data to the Weibull distribution. The computational results show that the proposed simulation method is more economical and reasonable for typhoon risk-assessment based on the indirect method. And using the proposed indirect method, the probabilistic design wind speed for transmission towers in typhoon-prone region along the South-Western coast is investigated.

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CORRECTION OF SECONDARY CLEFT-LIP NASAL DEFORMITY BY USING ABBE FLAP: REPORT OF 4 CASES (Abbe 피판을 이용한 이차성 구순열비변형의 교정 4예)

  • Ryu, Sun-Youl;Kim, Tae-Hee;Hwang, Ung;Koo, Hong;Kwon, Jun-Kyung;An, Jin-Suk;Park, Hong-Ju
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제29권1호
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    • pp.55-62
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    • 2007
  • Radical paring of the cleft edge during primary cleft lip operation or repeated secondary surgeries can result in tightness of the upper lip. In case, the degree of the resulting side-to-side tension is very severe, the possibility of a lip switch flap must be considered. When the lip tightness accompanies a loss of more than two-thirds of the Cupid's bow, an Abbe flap is an alternative. The disadvantages of Abbe flap are scar formation on the lower lip, design of incision line on the upper lip, disharmony of colors, and the dysfunction of the orbicularis muscle. These problems have been recognized in the literature and extreme discretion has been advised in its application. We experienced four cases of Abbe flap operation which were designed differently to correct the secondary unilateral or bilateral cleft-lip nasal deformities. The Abbe flap operations resulted in removal of the scars and tightness of the upper lip, reconstruction of the Cupid's bow, lengthening of the columella, and therefore secondary cleft-lip nasal deformity could be corrected. It is thought that carefully applied Abbe flap is an appropriate method to relieve horizontal tightness or flattening of the upper lip which occured after primary operation of cleft lip.

Median Control Chart for Nonnormally Distributed Processes (비정규분포공정에서 메디안특수관리도 통용모형설정에 관한 실증적 연구(요약))

  • 신용백
    • Journal of Korean Society of Industrial and Systems Engineering
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    • 제10권16호
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    • pp.101-106
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    • 1987
  • Statistical control charts are useful tools to monitor and control the manufacturing processes and are widely used in most Korean industries. Many Korean companies, however, do not always obtain desired results from the traditional control charts by Shewhart such as the $\bar{X}$-chart, $\bar{X}$-chart, $\bar{X}$-chart, etc. This is partly because the quality charterstics of the process are not distributed normally but are skewed due to the intermittent production, small lot size, etc. In Shewhart $\bar{X}$-chart. which is the most widely used one in Kora, such skewed distributions make the plots to be inclined below or above the central line or outside the control limits although no assignable causes can be found. To overcome such shortcomings in nonnormally distributed processes, a distribution-free type of confidence interval can be used, which should be based on order statistics. This thesis is concerned with the design of control chart based on a sample median which is easy to use in practical situation and therefore properties for nonnormal distributions may be easily analyzed. Control limits and central lines are given for the more famous nonnormal distributions, such as Gamma, Beta, Lognormal, Weibull, Pareto, Truncated-normal distributions. Robustness of the proposed median control chart is compared with that of the $\bar{X}$-chart; the former tends to be superior to the latter as the probability distribution of the process becomes more skewed. The average run length to detect the assignable cause is also compared when the process has a Normal or a Gamma distribution for which the properties of X are easy to verify, the proposed chart is slightly worse than the $\bar{X}$-chart for the normally distributed product but much better for Gamma-distributed products. Average Run Lengths of the other distributions are also computed. To use the proposed control chart, the probability distribution of the process should be known or estimated. If it is not possible, the results of comparison of the robustness force us to use the proposed median control chart based oh a normal distribution. To estimate the distribution of the process, Sturge's formula is used to graph the histogram and the method of probability plotting, $\chi$$^2$-goodness of fit test and Kolmogorov-Smirnov test, are discussed with real case examples. A comparison of the proposed median chart and the $\bar{X}$ chart was also performed with these examples and the median chart turned out to be superior to the $\bar{X}$-chart.

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Effects of Self Directed Learning Applying Basic Nursing Practice Contents of e-Learning on Nursing Students' Knowledge, Self Confidence and Satisfaction (e-Learning기본간호실습 콘텐츠를 이용한 자기주도학습이 간호학생의 지식, 자신감, 교육만족도에 미치는 효과)

  • Jo, Hyun-Sook;Park, Eun-Young;Choi, Jeong-Sil
    • The Journal of the Korea Contents Association
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    • 제13권9호
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    • pp.504-514
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    • 2013
  • Purpose: This study was to identify the educational effects of self directed learning applying basic nursing practice contents of e-learning on nursing students' knowledge, self-confidence, and learning satisfaction. Method: This study applied a quasi-experimental pre-test and post-test control group design with 63 freshman nursing students (31 experimental group, 32 control group) of G. university in Incheon, Korea as subjects. The e-learning content was about the application of topical medications, central line care, and blood transfusion. All were available at the web site in school. Self-directed e-learning was more than 120 min.(3 times a week, 2 weeks)during Sep-Nov in 2011. In both groups, there were no significant difference in general characteristics, self-directed learning readiness, knowledge, and self-confidence for the pre-homogeneity. Results: The experimental group showed a higher level of improvement in knowledge and learning satisfaction but not significantly. However, the self-confidence was significantly improved in the experimental group. Conclusion: When self-directed learning using e-learning contents added to the conventional practical class, it may be beneficial for the nursing students to learn skills effectively.

Design of the Flexible Buffer Node Technique to Adjust the Insertion/Search Cost in Historical Index (과거 위치 색인에서 입력/검색 비용 조정을 위한 가변 버퍼 노드 기법 설계)

  • Jung, Young-Jin;Ahn, Bu-Young;Lee, Yang-Koo;Lee, Dong-Gyu;Ryu, Keun-Ho
    • The KIPS Transactions:PartD
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    • 제18D권4호
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    • pp.225-236
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    • 2011
  • Various applications of LBS (Location Based Services) are being developed to provide the customized service depending on user's location with progress of wireless communication technology and miniaturization of personalized device. To effectively process an amount of vehicles' location data, LBS requires the techniques such as vehicle observation, data communication, data insertion and search, and user query processing. In this paper, we propose the historical location index, GIP-FB (Group Insertion tree with Flexible Buffer Node) and the flexible buffer node technique to adjust the cost of data insertion and search. the designed GIP+ based index employs the buffer node and the projection storage to cut the cost of insertion and search. Besides, it adjusts the cost of insertion and search by changing the number of line segments of the buffer node with user defined time interval. In the experiment, the buffer node size influences the performance of GIP-FB by changing the number of non-leaf node of the index. the proposed flexible buffer node is used to adjust the performance of the historical location index depending on the applications of LBS.

Performance Analysis of Adaptive SC/MRC Diversity Combining using in AWGN (AWGN환경에서 적응형 SC/MRC 다이버시티 컴바이너 성능분석)

  • Yun, Deok-Won;Huh, Sung-Uk;Kim, Chun-Won;Choi, Yong-Tae;Lee, Won-Cheol
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • 제11권6호
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    • pp.757-763
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    • 2018
  • It is very difficult to achieve sufficient data rate and required quality of service due to the time-varying nature of the radio channel and various jammers such as path loss, delay, Doppler, shadowing and interference. Especially, the propagation path between the transmitting antenna and the tracking antenna mounted on the fuselage during the test and evaluation of the projectile system considered in this paper is based on the rapid movement of the projectile, the interference due to multipath fading due to the terrain, The propagation path may be blocked. In order to effectively improve the multipath fading occurring in the wireless communication system, a diversity combiner technique is required. In this paper, to derive the design and improvement schemes for the space diversity combiner technique among the diversity combiner schemes, the BER performance of maximum ratio combining (MRC) and selection combining (SC) In an adaptive SC / MRC diversity combiner that operates with MRC when it is lower than the specified threshold criterion when comparing the SNR between two signals received from the channel and operates with SC at high and combines the two received signals The BER performance of the system was compared and analyzed.

A Study on The Factors of Policy Change in Latecomer Nations : Through the case of Korea's renewable energy policy change (후발국의 제도 변화 요인 연구 : 한국의 신재생에너지 정책 변동 사례를 통해)

  • Yoon, Youngchul;Choung, Jae-Yong
    • Journal of Technology Innovation
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    • 제27권2호
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    • pp.1-36
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    • 2019
  • In line with the international community's movement to reduce greenhouse gas emission, Korea implemented FIT(Feed in Tariff) in 2002 as part of its renewable energy development project. Although the policy had shifted to full-scale RPS(Renewable Portfolio Standards) in 2012, policymakers are still seeking changes due to policy ineffectiveness. While previous studies explain sudden policy changes through external factors, recent research sheds light on internal factors in the process of policy transition. The purpose of this study is to investigate the factors that are responsible for rapidly changing policies in latecomer nations. In order to find this, we look at the case of transition from the FIT to the RPS in Korea's expansion of renewable energy policy. As a result of the research, it is confirmed that the Top-Down decision making system of Korea and the external regulatory change cause rapid policy transition. By looking at these variables, we propose useful implications for policymakers to minimize the policy failure in future policy design and evolution.

Numerical Study on Towing Stability of LNG Bunkering Barge in Calm Water (LNG 벙커링 바지의 정수 중 예인안정성에 관한 수치연구)

  • Oh, Seung-Hoon;Jung, Dong-Ho;Jung, Jae-Hwan;Hwang, Sung-Chul;Cho, Seok-Kyu;Sung, Hong-Gun
    • Journal of Navigation and Port Research
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    • 제43권3호
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    • pp.143-152
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    • 2019
  • In this paper, the towing stability of the LNG bunker barge was estimated. Currently, LNG bunkering barge is being developed for the bunkering of LNG (Liquefied Natural Gas), an eco-friendly energy source. Since the LNG bunkering barge assumes the form of a towed ship connected to the tow line, the towing stability of the LNG bunker barge is crucial f not only for the safety of the LNG bunker barge but also the neighboring sailing vessels. In the initial stages, a numerical code for towing simulation was developed to estimate the towing stability of the LNG bunkering barge. The MMG (Maneuvering Mathematical modeling Group) model was applied to the equations of motion while the empirical formula was applied to the maneuvering coefficients for use in the initial design stage. To validate the developed numerical code, it was compared with published calculation and model test results. Towing simulations were done based on the changing skeg area and the towing position of the LNG bunkering barge using the developed numerical codes. As a result, the suitability of the designed stern skeg area was confirmed.

Analysis of braking characteristics of electric multiple unit for train control system (열차제어시스템을 위한 전동차 제동특성 분석)

  • Choi, Don Bum;Oh, Sehchan;Kim, Min-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • 제19권12호
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    • pp.887-895
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    • 2018
  • This paper presents a braking model that can be used to design the safety distance of a train control system and a train braking system to increase the volume of traffic. For the braking model, a train set (electric multiple unit composed 6 cars) was tested. The factors that can affect the braking characteristics include the friction coefficient, braking pressure, and regenerative braking. The braking pressure was classified into service and emergency braking and reflected the characteristics of the vehicle. The external force acting on the running railway car was tested in accordance with KS R 9217, and the running resistance of the train is presented in the form of a polynomial. The dynamic behavior of the train running on a straight flat line was simulated using UM 8.3. The results were validated with experimental data, and the results were reasonable. With the validated model, a stopping distance was determined according to the initial braking speed and compared with the deceleration braking model. In addition, a safety distance for the train control system could be changed according to the frictional coefficient limits. These results are expected to be useful for analyzing the dynamic behavior of trains, and for analyzing various railway environments and improving the braking performance.