• International Journal of Control, Automation, and Systems
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• v.5 no.4
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• pp.397-409
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• 2007

In this paper, we propose a nonlinear guidance law for missiles against maneuvering targets. First, we derive the equations of motion described in the line-of-sight reference frame and then we define the equilibrium subspace of the nonlinear system to guarantee target interception within a finite time. Using Sontag's formula, we derive a nonlinear guidance law that always delivers the state to the equilibrium subspace. If the speed of the missile is greater than that of the target, the proposed law has global capturability in that, under any initial launch conditions, the missile can intercept the maneuvering target. The proposed law also minimizes the integral cost of the control energy and the weighted square of the state. The performance of the proposed law is compared with the augmented proportional navigation guidance law by means of numerical simulations of various initial conditions and target maneuvers.

• Journal of Industrial Convergence
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• v.2 no.2
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• pp.47-68
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• 2004

The term "social marketing" was first introduced in 1971 to describe the use of marketing principles and techniques to advance a social cause, idea, or behavior. Social Marketing is a strategy for changing behavior. It utilizes concepts of market segmentation, consumer research, product concept development and testing, directed communication, facilitation, incentives, and exchange theory to maximize the target adopters' response. Social marketing requires knowledge of each target-adopter group, including its 1. social demographic characteristics, 2. psychological profile and 3. behavioral characteristics. To know the target adopters in these three related ways enables social marketer to make more accurate predictions. In addition to differentiating among and selecting target adopter groups, the social marketer will identify influence-holding groups, or influentials, who can affect a program's success. Great changes and opportunities exist to produce changes in the ways that individuals and groups think and behave and in meeting human needs. The balance of the scales of social change, we hope, will shift away from the use of force and violence to the use of persuasion and voluntary action. I trust that this dissertation will be useful highlighting the strategies and means of peaceful, planned social change designed to elevate the quality of life.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.1
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• pp.1-7
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• 2009

Purpose: The purpose is to evaluate the accuracy of correcting the targeting error through the Target Location System (TLS) for the location change error of the reference point which arises from the movement or motion of patient during the treatment using the CyberKnife. Materials and Methods: In this test, Gafchromic MD-55 film was inserted into the head and neck phantom to analyze the accuracy of the targeting, and then the 6 MV X-ray of CyberKnife (CyberKnife Robotic Radiosurgery System G4, Accuray, US) was irradiated. End to End (E2E) program was used to analyze the accuracy of targeting, which is provided by Accuray Corporation. To compute the error of the targeting, the test was carried out with the films that were irradiated 12 times by maintaining the distance within the rage of $0{\pm}0.2\;mm$ toward x, y, z from the reference point and maintaining the angle within the rage of $0{\pm}0.2^{\circ}$ toward roll, pitch, yaw, and then with the films which were irradiated 6 times by applying intentional movement. And the correlation in the average value of the reference film and the test film were analyzed through independent samples t-test. In addition, the consistency of dose distribution through gamma-index method (dose difference: 3%) was quantified, compared, and analyzed by varying the distance to agreement (DTA) to 1 mm, 1.5 mm, 2 mm, respectively. Results: E2E test result indicated that the average error of the reference film was 0.405 mm and the standard deviation was 0.069 mm. The average error of the test film was 0.413 mm with the standard deviation of 0.121 mm. The result of independent sampling t-test for both averages showed that the significant probability was P=0.836 (confidence level: 95%). Besides, by comparing the consistency of dose distribution of DTA through 1 mm, 1.5 mm, 2 mm, it was found that the average dose distribution of axial film was 95.04%, 97.56%, 98.13%, respectively in 3,314 locations of the reference film, consistent with the average dose distribution of sagittal film that was 95.47%, 97.68%, 98.47%, respectively. By comparing with the test film, it was found that the average dose distribution of axial film was 96.38%, 97.57%, 98.04%, respectively, at 3,323 locations, consistent with the average dose distribution of sagittal film which was 95.50%, 97.87%, 98.36%, respectively. Conclusion: Robotic CyberKnife traces and complements in real time the error in the location change of the reference point caused by the motion or movement of patient during the treatment and provides the accuracy with the consistency of over 95% dose distribution and the targeting error below 1 mm.

• Korean Journal of Cognitive Science
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• v.16 no.3
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• pp.175-188
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• 2005

Recently, Li, Brenner, Cornelissen and Kim (2002) reported that 2D shape perception during pursuit eye movement just reflected the retinal image, and this result implies that the visual system ignored the extra-retinal information. In reality, however, we usually do not experience the perceptual distottion of 2D shape during pursuit eye movement. One Possibility is that the visual system night exploit the fact that the relative location between objects on retinal image is constantly maintained even during pursuit eye movement. The present research examined this possibility. Interestingly, perceptual distortion of 2D shape was observed even in the presence of reference, however, the amount of distortion decreased compared to when the reference does not exist. The distance between the reference and the target affected the perceptual distortion. These results imply that reference information is used in 2D shape perception during pursuit eye movement but it cannot completely explain the stable and accurate representation of 2D shape perception during pursuit eye movement.

• Journal of Radiation Protection and Research
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• v.44 no.2
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• pp.72-78
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• 2019

Background: In the calibration and testing laboratory of Korea Atomic Energy Research Institute, the old X-ray generator used for the production of reference X-ray fields was replaced with a new one. For this newly installed X-ray irradiation system, beam alignment as well as the verification of beam qualities was conducted. Materials and Methods: The existing X-ray generator, Phillips MG325, was replaced with YXLON Y.TU 320-D03 in order to generate reference X-ray fields. Theoretical calculations and Monte Carlo simulations were used to determine initial filter thickness. Beam alignment was performed in three steps to deliver a homogeneous radiation dosage to the target at different distances. Finally, the half-value layers were measured for different X-ray fields to verify beam qualities by using an ion chamber. Results and Discussion: Beam alignment was performed in three steps, and collimators and other components were arranged to maintain the uniformity of the mean air kerma rate within ${\pm}2.5%$ at the effective beam diameter of 28 cm. The beam quality was verified by using half-value layer measurement methods specified by American National Standard Institute (ANSI) N13.11-2009 and International Organization for Standardization (ISO)-4037. For each of the nine beams than can be generated by the new X-ray irradiation system, air kerma rates for X-ray fields of different beam qualifies were measured. The results showed that each air kerma rate and homogeneity coefficient of the first and second half-value layers were within ${\pm}5%$ of the recommended values in the standard documents. Conclusion: The results showed that the new X-ray irradiation system provides beam qualities that are as high as moderate beam qualities offered by National Institute of Standards and Technology in ANSI N13.11-2009 and those for narrow-spectrum series of ISO-4037.

• Journal of Soil and Groundwater Environment
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• v.26 no.3
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• pp.37-49
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• 2021

There is domestic Soil Contamination Warning Standard (SCWS) as remediation standard concentration of contaminated soils. No risk should be observed at soil concentration less than SCWS. Therefore, SCWS was evaluated to confirm the risk assessment. Background Concentration of Soil (BGC) and target remediation concentration were also assessed. The results show that Excess Cancer Risk (ECR) of SCWS was the highest in the groundwater intake pathway (Adult: 6.27E-04, Child: 2.81E-04). Total Cancer Risk (TCR) was 7.76E-04 and 4.30E-04 for adult and child, exceeding reference value (10^-6). Hazard Quotient (Non-Carcinogenic Risk, HQ) was the highest in the indoor air inhalation pathway (Adult: 3.64E+03, Child: 8.74E+02). Hazard Index (Total Non-Carcinogenic Risk, HI) exceeded reference value 1. ECR of the BGC was the highest in the groundwater intake pathway (Adult: 1.71E-04, Child: 7.67E-05). TCR was 2.12E-04 for adults and 1.17E-04 for children, exceeding the reference value (10^-6). HQ was the highest in groundwater intake pathway (Adult: 4.10E-01, Child: 1.84E-01). HI was lower than reference value 1 (Adult: 4.78E-01, Child: 2.50E-01). The heavy metal affecting ECR was Arsenic (As). The remediation-concentration of As was 7.14 mg/kg which is higher than BGC (6.83 mg/kg). TCR of As should be less than reference value (10^-6), but it was higher for all of SCWS, BGC and target remediation concentration. Therefore, it is suggested that risk assessment factors should be re-evaluated to fit domestic environmental settings and SCWS should be induced to satisfy the risk assessment.

• Communications of Mathematical Education
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• v.25 no.1
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• pp.21-45
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• 2011

It is the aim of this paper to find the requisites for the target problem solving process in reference to the base problem and to search the roles of those. Focusing on the structural similarity, analytic activity and comparative activity in stage of similar mathematical problem solving process, we tried to find the roles of them. We observed closely how four students solve the target problem in reference to the base problem. And so we got the following conclusions. The insight of structural similarity prepare the ground appling the solving method of base problem in the process solving the target problem. And we knew that the analytic activity can become the instrument which find out the truth about the guess. Finally the comparative activity can set up the direction of solution of the target problem. Thus we knew that the insight of structural similarity, the analytic activity and the comparative activity are necessary for similar mathematical problem to solve. We think that it requires the efforts to develop the various programs about teaching-learning method focusing on the structural similarity, analytic activity and comparative activity in stage of similar mathematical problem solving process. And we also think that it needs the study to research the roles of other elements for similar mathematical problem solving but to find the roles of the structural similarity, analytic activity and comparative activity.

• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.115-127
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• 2021

With the development of science and technology around the world, the realm of cyberspace, following land, sea, air, and space, is also recognized as a battlefield area. Accordingly, it is necessary to design and establish various elements such as definitions, systems, procedures, and plans for not only physical operations in land, sea, air, and space but also cyber operations in cyberspace. In this research, the importance of cyber targets that can be considered when prioritizing the list of cyber targets selected through intermediate target development in the target development and prioritization stage of targeting processing of cyber operations was selected as a factor to be considered. We propose a method to calculate the score for the cyber target and use it as a part of the cyber target prioritization score. Accordingly, in the cyber target prioritization process, the cyber target importance category is set, and the cyber target importance concept and reference item are derived. We propose a TIR (Target Importance Rank) algorithm that synthesizes parameters such as Event Prioritization Framework based on PageRank algorithm for score calculation and synthesis for each derived standard item. And, by constructing the Stuxnet case-based network topology and scenario data, a cyber target importance score is derived with the proposed algorithm, and the cyber target is prioritized to verify the proposed algorithm.

• International Journal of Control, Automation, and Systems
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• v.1 no.1
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• pp.83-92
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• 2003

The outdoor antenna servo system is subject to has significant torque disturbances from wind pressures and gusts on the antenna structures, as well as bearing and aerodynamic frictions. This control system should provide a sharp directivity in spite of the environmental disturbances and internal uncertainties. Therefore, the implementation of a real-time controller is necessary for the precise generation of the reference signal and robust tracking performance. In this paper, the discrete-time controller for the quick tracking of a target communication satellite is designed by applying the sampled-data $H_{\infty}$ control theory along with the reference signal generated by an improved conventional step-tracking algorithm. The sampled-data $H_{\infty}$controller demonstrates superior robustness for the longer sampling period when compared with a simple PID controller.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.93-97
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• 2005

This paper proposes a design of stepper motor control in microstep driven mode using FPGA (Field Programmable Gate Array) for hardware implementation. The methods to drive stepper motor in microstep excitation mode are to control of the controlling currents in each phase windings of stepper motor with reference signals. These reference signals are used for controlling the current levels, the required variation of current levels with rotor position can be obtained from the ideal linear or sinusoidal approximations to the static torque-displacement ($T-{\theta}$) characteristic curve. In addition, the hardware implementation of stepper motor controller can be designed uses VHDL (Very high speed integrated circuits Hardware Description Language) and synthesis using an Altera FPGA, FLEX10K family, EPF10K20RC240-4 device as target technology and use MAX+PlusII program for overall development. A multi-stack variable-reluctance stepper motor of Sanyo Denki is used in the experiments.