• Imaging Science in Dentistry
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• v.35 no.3
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• pp.121-125
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• 2005

Purpose : The purpose of this study was to investigate whether the fractal dimension of successive panoramic radiographs of bone after implant placement is useful in the characterization of structural change in alveolar bone. Materials and Methods. Twelve subjects with thirty-five implants were retrospectively followed-up from one week to six months after implantation. Thirty-six panoramic radiographs from twelve patients were classified into 1 week, 1-2 months and 3-6 months after implantation and digitized. The windows of bone apical and mesial or distal to the implant were defined as periapical region of interest (ROI) and interdental ROI; the fractal dimension of the image was calculated. Results There was not a statistically significant difference in fractal dimensions during the period up to 6 months after implantation. The fractal dimensions were higher in 13 and 15mm than 10 and 11.5mm implant length at interdental ROIs in 3-6 months after implantation (P<0.01). Conclusion : Longer fixtures showed the higher fractal dimension of bone around implant. This investigation needs further exploration with large numbers of implants for longer follow-up periods.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.2
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• pp.45-51
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• 2000

This study proposes that analysis and evaluation method of time series ultrasonic signal using the chaotic feature extrac-tion for degradation extent. Features extracted from time series data using the chaotic time series signal analyze quantitatively material degradation extent. For this purpose analysis objective in this study if fractal dimension lyapunov exponent and strange attractor on hyperspace. The lyapunov exponent is a measure of the rate at which nearby trajectories in phase space diverge. Chaotic trajectories have at least one positive lyapunov exponent. The fractal dimension appears as a metric space such as the phase space trajectory of a dynamical syste, In experiment fractal(correlation) dimensions and lyapunov experiments showed values of mean 3.837-4.211 and 0.054-0.078 in case of degradation material The proposed chaotic feature extraction in this study can enhances ultrasonic pattern recognition results from degrada-tion signals.

• Journal of Welding and Joining
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• v.16 no.6
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• pp.86-96
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• 1998

This study proposes the analysis method of time series ultrasonic signal using the chaotic feature extraction for degradation extent evaluation. Features extracted from time series data using the chaotic time series signal analyze quantitatively degradation extent. For this purpose, analysis objective in this study is fractal dimension, lyapunov exponent, strange attractor on hyperspace. The lyapunov exponent is a measure of the rate at which nearby trajectories in phase space diverge. Chaotic trajectories have at least one positive lyapunov exponent. The fractal dimension appears as a metric space such as the phase space trajectory of a dynamical system. In experiment, fractal correlation) dimensions, lyapunov exponents, energy variation showed values of 2.217∼2.411, 0.097∼ 0.146, 1.601∼1.476 voltage according to degardation extent. The proposed chaotic feature extraction in this study can enhances precision ate of degradation extent evaluation from degradation extent results of the degraded materials (SA508 CL.3)

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.2
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• pp.119-128
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• 1994

There are three important regions im Multiple Objective Linear Programming (MOLP). One is the region of efficient solutions, another is the region of weight to be used for finding efficient solutions, the third is the region of efficient (nondominated) objective values. In this paper, first, we find the condition of extreme point in the region of efficient objective values. Second, we find that the sum of the dimension of the weight region and the dimension of efficient objective values region is constant. Using the above, it is shown that we find the shape and dimension of weight region corresponding to the given region or efficient objective values and vice versa.

• Communications for Statistical Applications and Methods
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• v.22 no.3
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• pp.305-312
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• 2015

We extend a generalized partially linear single-index model and newly define a generalized partially double-index model (GPDIM). The philosophy of sufficient dimension reduction is adopted in GPDIM to estimate unknown coefficient vectors in the model. Subsequently, various combinations of popular sufficient dimension reduction methods are constructed with the best combination among many candidates determined through a bootstrapping procedure that measures distances between subspaces. Distinguishing values are newly defined to match the estimates to the corresponding population coefficient vectors. One of the strengths of the proposed model is that it can investigate the appropriateness of GPDIM over a single-index model. Various numerical studies confirm the proposed approach, and real data application are presented for illustration purposes.

• Bulletin of the Korean Mathematical Society
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• v.29 no.1
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• pp.117-123
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• 1992

The dimension problem has been one of central themes in the theory of ordered sets. In this paper we focus on amalgamated ordered sets. Although some results can be obviously applied to infinite cases, we assume throughout that all ordered set are finite. If A and B are ordered sets whose orders agree on A.cap.B, then the amalgam of A and B is defined to the the set A.cup.B in which the order is the transitive closure of the union of the two orders, i.e., the smallest order containing the two orders, and is denoted by A .or. B .leq. dim A + dim B for any ordered sets A and B. But it is quite surprising that the dimension of the amalgam of certain 2-dimensional ordered sets can be arbitrarily large.

• The Journal of Information Technology and Database
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• v.8 no.1
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• pp.41-65
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• 2001

This study proposes evaluation dimensions of object-oriented systems modelling tools and activities available in object-oriented systems development practices. The dimensions ale developed based on previous research in cognitive psychology, information systems modeling study, and object-oriented systems analysis arid design areas. The proposed dimension is composed of two dimensions. The one dimension includes abstraction levels of modelling and the other includes process and representation in modeling activities. Experts on object-oriented modeling were selected to evaluate the practical validity of the proposed dimensions and applications of major object-oriented modeling tools during systems development project. Most of the tools were observed to be used for representing objects rather than for modeling the process of related objects. The proposed modeling dimension will be evaluated for acquiring general validity in future empirical research.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.602-607
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• 1990

Spent nuclear fuel is very dangerous substance emitting strong ionizing radiation which is harmful to human body. The remote handling of spent nuclear fuel is essential because people cannot access this substance without protecting radiation. To handle highly radioactive material or nuclear waste, many kinds of teleoperators such as master slave manipulator, electro mechanical manipulator, servo manipulator, mobile robot was developed. The distance and dimension of target object cannot be measured easily when highly radioactive material is handled by teleoperator because one should use lead glass or TV camera and monitor to protect radiation and see target object. During experiments on the remote handling of spent nuclear fuel by electro mechanical manipulator, we often felt that a distance and dimension measurement system is necessary to handle the objects which is in the highly radioactive environment, so we developed a system which is appropriate for this purpose.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.211-211
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• 2000

The multiple targets tracking problem has been one of main issues in the radar applications area in the last decade. Besides the standard Kalman filtering, various methods including the variable dimension filter, input estimation filter, interacting multiple model (IMM) filter, federated variable dimension filter with input estimation, probable data association (PDA) filter etc. have been proposed to address the tracking and sensor fusion issues. In this paper, two existing tracking algorithms, i.e. the IMMPDA filter and the variable dimension filter with input estimation (VDIE), are combined for the purpose of improving the tracking performance of maneuvering targets in clutter. To evaluate the tracking performance of the proposed algorithm, three typical maneuvering patterns i.e. Waver, Pop-Up, and High-Diver motions, are defined and are applied to the modified IMMPDA filter considered as well as the standard IMM filter. The smaller RMS tracking errors, in position and velocity, of the modified IMMPDA filter than the standard IMM filter are demonstrated through computer simulations.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.443-450
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• 2023

One of the basic tasks in the automobile manufacturing process is to design a bare chassis, which is the basic frame of a vehicle, and a bracket is a member connecting various devices to the frame. Bracket, which is a member connecting the engine, transmission, and suspension, which are the core devices of driving and operating the vehicle, to the frame, must maintain safety during vehicle operation. If the bracket connecting the various devices constituting the vehicle to the frame does not have durability, serious accidents may occur during operation of the vehicle. In this study, we performed stress analysis on the brackets installed in the bare chassis of the 25-passenger bus in the development stage. Based on the stress analysis performed, an improved bracket dimension was proposed.