• Management Science and Financial Engineering
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• v.10 no.1
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• pp.97-106
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• 2004

In this paper, we propose an effective cut generation method based on the Chvatal-Gomory procedure for a variable-capacity (0,l)-Knapsack problem with two general integer variables. We first derive a class of valid inequalities for the problem using Chvatal-Gomory procedure, then analyze the associated separation problem. Based on the results, we show that there exists a pseudo-polynomial time algorithm to solve the separation problem. By analyzing the theoretical strength of the inequalities which can be generated by the proposed cut generation method, we show that generated inequalties define facets under mild conditions. We also extend the result to the case in which a nontrivial upper bound is imposed on a general integer variable.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.120-127
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• 2008

The constant velocity joint(CVJ) used for transmitting torque to the front wheels is an important part in automotive drive system. There are several types of constant velocity joints. Typically, they are classified by fixed and plunging constant velocity joints. The axial force generated in plunging constant velocity joints influences significantly the noise, vibration and harshness. For heaps of time, many constant velocity joint markers have been studying and developing a valid method to reduce the axial force and extensive tests have been carried out on rigs. This paper presents the analysis method to predict the axial force of a double offset constant velocity joint(DOJ), a kind of plunging constant velocity joint, and the influence of ball-cage dimension tolerance on the axial force.

• Knowledge Management Research
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• v.11 no.1
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• pp.65-81
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• 2010

This paper explores the determinants of the economic value of patents using a survival time analysis. The analysis is based on renewal information of about 250,000 patents filed from 1984 to 2005 in the Korea Intellectual Property Office. A patent right is valid only when its owner pays yearly maintenance fees. Failure to pay causes patent rights to be lapsed. We use the fact that more valued patents live longer and the lengths of their renewals can be closely related to their value. The value can be affected not only by its own technological aspects such as quality and breadth, but also by characteristics of its owners such as innovativeness and age. This paper presents patent-specific and firm-specific characteristics which influence patent value. The result of analysis implies that patent value depends on both the technological contents of the patent and general capabilities of a firm.

• Nutritional Sciences
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• v.7 no.1
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• pp.53-58
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• 2004

The Multiethnic Cohort Study was designed to study prospectively the relationship of diet and other lifestyle factors to the risk of cancer. The cohort was established in 1993-1996 in Hawaii and California (primarily Los Angeles) and included a representative sample of more than 215,000 men and women primarily from five different ethnic groups: Japanese, whites, Native Hawaiians, Latinos, and African- Americans. Because of the emphasis on diet, great attention was paid to developing and pre-testing a self-administered quantitative food frequency questionnaire that would adequately assess food and nutrient intakes in these groups. An extensive food composition database was also created for the study. In addition, during data collection, a calibration study was conducted that makes possible adjustment for measurement error in nutrient intakes and valid comparison of intakes across the several ethnic groups. At the present time, blood and urine specimens are being collected from cohort participants and should yield a biorepository of more than 80,000 subjects. Baseline data indicate that the cohort is well representative of the general population of Hawaii and California, so that results can be generalized. These data also show a wide range in dietary intakes and in other lifestyle variables that should facilitate the testing of etiologic hypotheses.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1265-1278
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• 2017

Dynamic task scheduling is one of the most popular research topics in the cloud computing field. The cloud scheduler dynamically provides VM resources to variable cloud tasks with different scheduling strategies in cloud computing. In this study, we utilized a valid model to describe the dynamic changes of both computing facilities (such as hardware updating) and request task queuing. We built a novel approach called Policy Iteration Scheduling (PIS) to globally optimize the independent task scheduling scheme and minimize the total execution time of priority tasks. We performed experiments with randomly generated cloud task sets and varied the performance of VM resources using Poisson distributions. The results show that PIS outperforms other popular schedulers in a typical cloud computing environment.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.346-350
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• 1989

This paper concerned about a study on the position control of KED-1 robot manipulator using PID self-tuning controller. For two joint manipulator KED-1, KED-1 manipulator is translated into kinematics to control each joints in joint space seheme. Angle displacements of joint coordinate are transformed into reference angle velocity of each subsystem through trajectory planning. Also, time sharing technique is used to control KED-1 manipulator. A series of simulation and experiment are performed for each joint in show the valid of proposed algorithm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.28-32
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• 1993

A deposition rate of styrene thin films is linearly increased, but one of benzene thin films is nonlinearly increased with increasing discharge power under maintaining a polymerization time, pressure and monomer flow rate. And, the reduction of transmittance at shortwave is larger than that of transmittance at longwave. The refractive index with wavelength is various from 1.55 to 1.65. The refractive index of their thin films is decreased with increasing discharge power. Also, it is known that measured results are valid because the calculation of the extinction coefficient is about $10^3$ within variation of refractive index.

• ETRI Journal
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• v.29 no.4
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• pp.430-436
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• 2007

An OFDM/offset QAM (OQAM)-IOTA system uses the isotropic orthogonal transform algorithm (IOTA) function, which has good localization properties in the time and frequency domains. This is employed instead of the guard interval used in a conventional OFDM/QAM system in order to be robust for multi-path channels. However, the conventional channel estimation scheme is not valid for an OFDM/OQAM-IOTA system due to the intrinsic inter-symbol interference of the IOTA function. In this paper, a condition is derived to reduce the intrinsic interference of the IOTA function. This condition is obtained with the proposed pilot structure used for perfect channel estimation. We also derive the preamble structure appropriate for practical channel estimation of the OFDM/OQAM-IOTA system. Simulation results show that the OFDM/OQAM-IOTA system with the proposed preamble structure performs better than the conventional OFDM system, and it has the additional advantage of an increased data transmission rate which corresponds to the guard interval retrieval.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.517-520
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• 2003

The snow-fatting measurement system including the snow sensor applying the photo-coupler is investigated in this study and using this snow sensor the height of snow fallen is measured. To measure the snow depth, five photo sensors are arranged with 5 mm distance. The snow-falling measurement system, which is measuring the motor revolution controlled with stepping motor, is mounted above the snow surface. From this work, it is feasible to measure quantitatively the snow on real time. Its software implements a proven method to achieve valid measurements also under difficult conditions as future study. In cases where the snow sensor is applieded to the prediction of snow in the meteorological observation system and the snow removing system, it is recommend the GRS-Option in order to improve the quality of snow measurements for better compensation.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.3
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• pp.147-156
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• 2008

A new approach based on cone prism intersection method combined with sorting algorithm is proposed for the fast and robust signed distance field computation. In the method, the space bounding the geometric model composed of triangular net is divided into multiple smaller cells. For the efficient calculation of distance fields, valid points among the triangular net which will generate minimum distances with current cell are selected by checking the intersection between current cell and cone prism generated at each point. The method is simple to implement and able to achieve an order of magnitude improvement in the computation time as compared to earlier approaches. Further the method is robust in handling the traditional sign problems. The validity of the suggested method was demonstrated by providing numerous examples including Boolean operation, shape deformation and morphing of complex geometric models.