• Title/Summary/Keyword: Infinite time scale process

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A Study on Optimal Release Time for Software Systems based on Generalized Gamma Distribution (일반화 감마분포에 근거한 소프트웨어 최적방출시기에 관한 비교 연구)

  • Kim, Jae-Wook;Kim, Hee-Cheul
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.6 no.1
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    • pp.55-67
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    • 2010
  • Decision problem called an optimal release policies, after testing a software system in development phase and transfer it to the user, is studied. The applied model of release time exploited infinite non-homogeneous Poisson process. This infinite non-homogeneous Poisson process is a model which reflects the possibility of introducing new faults when correcting or modifying the software. The failure life-cycle distribution used generalized gamma type distribution which has the efficient various property because of various shape and scale parameter. Thus, software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement becomes an optimal release policies. In a numerical example, after trend test applied and estimated the parameters using maximum likelihood estimation of inter-failure time data, estimated software optimal release time.

An Empirical Central Limit Theorem for the Kaplan-Meier Integral Process on [0,$\infty$)

  • Bae, Jong-Sig
    • Journal of the Korean Statistical Society
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    • v.26 no.2
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    • pp.231-243
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    • 1997
  • In this paper we investigate weak convergence of the intergral processes whose index set is the non-compact infinite time interval. Our first goal is to develop the empirical central limit theorem as random elements of [0, .infty.) for an integral process which is constructed from iid variables. In developing the weak convergence as random elements of D[0, .infty.), we will use a result of Ossiander(4) whose proof heavily depends on the total boundedness of the index set. Our next goal is to establish the empirical central limit theorem for the Kaplan-Meier integral process as random elements of D[0, .infty.). In achieving the the goal, we will use the above iid result, a representation of State(6) on the Kaplan-Meier integral, and a lemma on the uniform order of convergence. The first result, in some sense, generalizes the result of empirical central limit therem of Pollard(5) where the process is regarded as random elements of D[-.infty., .infty.] and the sample paths of limiting Gaussian process may jump. The second result generalizes the first result to random censorship model. The later also generalizes one dimensional central limit theorem of Stute(6) to a process version. These results may be used in the nonparametric statistical inference.

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Onset of Inertial Oscillation in a Rotating Flow (회전유동에서의 관성진동 원인규명)

  • Park, Jun-Sang
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2536-2539
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    • 2008
  • A study has been made on how to occur inertial oscillations in a rotating flow. The flow is considered to be induced by differentially-rotating top and bottom disks with infinite radius. The top and bottom disks are assumed to be set in motion over a finite initial start-up time duration from initial solid body rotation ($\Omega$) to each finial state, i.e., the top disk is rotating at the angular velocity (${\Omega}+{\Delta}{\Omega}$) and the bottom disk (${\Omega}-{\Delta}{\Omega}$). The system Reynolds number, which is a reciprocal of conventional Ekman number in rotating flows, is very high so that a boundary layer flow near disks is pronounced. From a strict theoretical analysis, it is clearly found the fact that inertial oscillation in a rotating flow is caused by excessive input of torque during start-up phase. Above finding comes from the following physics of theoretical result: in the case of abrupt start-up within very shorter time-duration than spin-up time scale, the inertial oscillation is magnified but it could be completely depressed in the case of mildly accelerated start-up, i.e., start-up process being established over diffusion time scale.

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Effects of the Tool Path on the Geometric Characteristics of Milled Surface (가공경로가 밀링가공면의 기하학적 특성에 미치는 영향)

  • Park, Moon-Jin;Kim, Kang
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.6
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    • pp.58-63
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    • 1998
  • There are lots of factors that are related to the geometric characteristics of machined surface. Among them, the tool path and milling mode (up cut milling or down cut milling) are the easiest controllable machining conditions. Thus, the first objective of this research is to study the effects of them on the milled surface that is generated by an end milling tool. To get precision parts, not only the machining process but also the measurement of geometric tolerance is important. But, this measurement requires a lot of time, because the infinite surface points must be measured in the ideal case. So, the second objective is to propose a simple flatness measurement method that can be available instead of the 3-D geometric tolerance measurement method, using a scale factor and characterized points. Finally, it is also shown that the possibility of flatness improvement by shifting the consecutive fine cutting tool path as compared with the last rough cutting tool path.

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Study about Utilizing the Wedding Dress Virtual Fitting Application Content (웨딩드레스 버추얼 피팅을 위한 애플리케이션 콘텐츠 활용 연구)

  • O, Ji-Hye;Lee, In-Seong
    • Journal of the Korean Society of Costume
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    • v.62 no.6
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    • pp.139-153
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    • 2012
  • To prolong the rapid progress of IT, it is necessary to develop contents through IT convergence among the existing goods & service and process areas to create new added-values. In particular, the wedding dress industry has infinite potential in utilizing various contents like virtual fitting by connecting with newly compelling IT areas such as smart phones, Augmented Reality (AR), and application contents. In the meantime, a large scale of the wedding industry has gained global competitiveness due to consulting expertise and the influence of the Korean Wave, whereas most small-sized wedding dress shops in Korea fall short of developing wedding dress designs and receiving relevant information. Accordingly, the purpose of this study was to help brides who have difficulties in choosing a wedding dress by decreasing their time and effort by providing wedding dress designs and information, according their desired image, body type, and circumstances through the utilization of virtual fitting application contents. Not only that, this study aims to diversify and specialize in wedding information and to help users to set a guideline for wedding dresses that are most suitable for them. Moreover, this study has an academic meaning in proposing an interdisciplinary convergence research model through the study of wedding dress design development, AR, and application contents utilization.

Object Tracking Based on Exactly Reweighted Online Total-Error-Rate Minimization (정확히 재가중되는 온라인 전체 에러율 최소화 기반의 객체 추적)

  • JANG, Se-In;PARK, Choong-Shik
    • Journal of Intelligence and Information Systems
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    • v.25 no.4
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    • pp.53-65
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    • 2019
  • Object tracking is one of important steps to achieve video-based surveillance systems. Object tracking is considered as an essential task similar to object detection and recognition. In order to perform object tracking, various machine learning methods (e.g., least-squares, perceptron and support vector machine) can be applied for different designs of tracking systems. In general, generative methods (e.g., principal component analysis) were utilized due to its simplicity and effectiveness. However, the generative methods were only focused on modeling the target object. Due to this limitation, discriminative methods (e.g., binary classification) were adopted to distinguish the target object and the background. Among the machine learning methods for binary classification, total error rate minimization can be used as one of successful machine learning methods for binary classification. The total error rate minimization can achieve a global minimum due to a quadratic approximation to a step function while other methods (e.g., support vector machine) seek local minima using nonlinear functions (e.g., hinge loss function). Due to this quadratic approximation, the total error rate minimization could obtain appropriate properties in solving optimization problems for binary classification. However, this total error rate minimization was based on a batch mode setting. The batch mode setting can be limited to several applications under offline learning. Due to limited computing resources, offline learning could not handle large scale data sets. Compared to offline learning, online learning can update its solution without storing all training samples in learning process. Due to increment of large scale data sets, online learning becomes one of essential properties for various applications. Since object tracking needs to handle data samples in real time, online learning based total error rate minimization methods are necessary to efficiently address object tracking problems. Due to the need of the online learning, an online learning based total error rate minimization method was developed. However, an approximately reweighted technique was developed. Although the approximation technique is utilized, this online version of the total error rate minimization could achieve good performances in biometric applications. However, this method is assumed that the total error rate minimization can be asymptotically achieved when only the number of training samples is infinite. Although there is the assumption to achieve the total error rate minimization, the approximation issue can continuously accumulate learning errors according to increment of training samples. Due to this reason, the approximated online learning solution can then lead a wrong solution. The wrong solution can make significant errors when it is applied to surveillance systems. In this paper, we propose an exactly reweighted technique to recursively update the solution of the total error rate minimization in online learning manner. Compared to the approximately reweighted online total error rate minimization, an exactly reweighted online total error rate minimization is achieved. The proposed exact online learning method based on the total error rate minimization is then applied to object tracking problems. In our object tracking system, particle filtering is adopted. In particle filtering, our observation model is consisted of both generative and discriminative methods to leverage the advantages between generative and discriminative properties. In our experiments, our proposed object tracking system achieves promising performances on 8 public video sequences over competing object tracking systems. The paired t-test is also reported to evaluate its quality of the results. Our proposed online learning method can be extended under the deep learning architecture which can cover the shallow and deep networks. Moreover, online learning methods, that need the exact reweighting process, can use our proposed reweighting technique. In addition to object tracking, the proposed online learning method can be easily applied to object detection and recognition. Therefore, our proposed methods can contribute to online learning community and object tracking, detection and recognition communities.