• The Transactions of the Korea Information Processing Society
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• v.2 no.4
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• pp.561-566
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• 1995

In the degraded mode, there is frequency-misalignment between the node clocks in a synchronous network. Therefore the phase differences between node clocks fluctuate greatly. To keep the phase difference under allowable level the pointer adjustment technique is used Unfortunately these processes cause an inherent pointer adjustment jitter, that accumulates in a chain of pointer adjustment systems. To analyze the jitter, computer simulation is carried and the results is compared with experimental jitter values.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.8
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• pp.440-447
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• 1999

This paper proposes a control method for three-phase PWM rectifier with only single current sensor in DC link side. A PWM modulation strategy for reconstructing three phase currents from the DC link current is given. The states of the retifier switch are modified so that all phase currents can be reconstructed in a switching period although one or two of active vectors is applied only for a short time. Therefore, a new current control using an adjustment scheme of the modulation signal for three-phase PWM rectifier will be discussed, and verified the experimental results.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.72-76
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• 2015

Capital project benchmarking requires an effective cost normalization process to compare cost performance of projects accomplished in different time and location. Existing cost normalization approaches have been established based on the assumption that all required information for cost normalization is fully identified once a project is completed. Cost normalization, however, is sometimes required to evaluate phase-level outcomes of an ongoing project where the required information is not fully available. This paper aims to provide a cost normalization procedure for phase-based performance assessment. The procedure consists of three normalization steps: currency conversion, location adjustment, and time adjustment considering various scenarios where the required information is not fully identified. This paper also presents how the cost normalization procedure has been applied to the 10-10 Performance Assessment Program, which is a phase-based performance assessment system developed by the Construction Industry Institute (CII). Both researchers and industrial professionals can apply the cost normalization procedure to studies and practices regarding to cost estimation, feasibility analysis, and performance assessment.

• Management Science and Financial Engineering
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• v.7 no.2
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• pp.73-90
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• 2001

This paper presents the reliability models for redundant systems composed of repairable components whose failure time and repair time distributions are phase-type. It is shown that the distribution of time to system failure is also phase-type. The dependency between components are considered and integrated into the model by the used of the rate adjustment factor. The phase-type representation is constructed for the system through algebraic operations on the parameters of components\` failure time and repair time distributions and the corresponding rate adjustment factors. Types of system structures considered are parallel, k-out-of-N system with load sharing scheme and standby system with operation priority.

• Journal of KSNVE
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• v.6 no.6
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• pp.701-708
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• 1996

Diesel power plants are frequently used as a power supplier on the island and the isolated places where electric power is required. The heat efficiency of the low speed 2 stroke diesel engines is higher than those of 4 stroke diesel engines or other heat engines and further its mobility and durability is also better than other engines. They can be also easily repaired and maintained. With these advantages, demand for the use of the low speed 2 stroke diesel engine as a power source is increasing. However, there are some disadvantages with these diesel engines such as the bigger vibrating excitation forces generated by higher combustion pressure in cylinder and by the inertia force of the reciprocating parts. Further, engine vibrations are transfered into their adjacent buildings and manufacturing factories and eventually produces local vibrations. In order to reduce X-mode vibration of engine body, several methods have been introduced in the recent researches. In this paper, accordingly, a new vibrationcontrol method applying a synchrophaser and a top bracing between two diesel engines is adopted in order to reduce these structural vibrations of diesel power plant. It was experimentally verified that the structural vibrations were greatly reduced by the phase adjustment for the 6th order X-mode vibration with the synchrophaser and the top bracing.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.1
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• pp.20-27
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• 2003

In this study, we designed and made Ultrasonic motor-digital multi controller(USM-DMC) using FPGA chip, A54SX72A made in Actel Corporation. By the minute, USM-DMC can adjust the frequency, duty ratio, and phase difference parameters of USM by digital input to be each 11bit from PC. Therefore, when we use this controller, it is possible to apply typical three parameters individually as well as multi-parameters simultaneously to control the speed and the torque. What is more, the strongest point is that it can trace frequency based on optimized frequency as compared with the phase difference because we can input optimized resonant frequency while in motoring. And we test the speed of USM with the adjustment of multi-parameters, the phase difference-frequency. As the result of the test, in the case of the multi-parameters of the phase difference and frequency, the speed characteristic is more linear and stable, and wider in the range of control than the single-parameter of the phase difference or the frequency.

• IE interfaces
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• v.22 no.3
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• pp.263-277
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• 2009

This research deals with a task assignment problem to worker group which consists of one master and one assistant. Each task must be assigned to only one worker group and it is possible to make a pair of each master and each assistant to organize a worker group. A worker group may have more than one task assigned to it, but the workloads of each worker group must be balanced within the allowable range. This problem can be formulated mathematically using the Mixed Integer Programming(MIP), where the objective function is to minimize the total assignment cost. A two phase heuristic algorithm is suggested in order to find approximate solutions. The first phase is to obtain an initial solution, where the initial assignment is performed to follow the workload adjustment. In the second phase, the solution is improved through the repeated process of the exchange and the assignment adjustment. Numerical experiments have been performed to evaluate the performance of the heuristic algorithm.

• Journal of Power Electronics
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• v.14 no.3
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• pp.541-548
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• 2014

This paper presents a simple lead angle adjustment method for brushless DC motors. The proposed method is based on the motor current dynamics analysis during the current commutation interval. With the proposed scheme, the phase current and phase back-EMF voltage are in phase and the BLDC motor and drive system have a high efficiency induced by the reduced copper and conduction losses. Experimental results are shown to validate the proposed method.

• Journal of Korean Academy of Nursing
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• v.17 no.1
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• pp.24-32
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• 1987

This study was designed to investigate the changes of nurses' role model, perceptions toward occupation, and self actualization value in terms of the phases of socialization process. Two hundred and sixty nine nurses working in clinical settings were randomly selected from 15 general hospitals despersed over Seoul and Kyungki province. Data were gathered by the standardized Perceptual Orientation Test, the Self-actualization Test, and Questionnaires on role models and phases of socialization process developed by the investigators from October 1985 to March 1986. The data were analysed by ANOVA and Pearson's Correlation Coefficient. The results were as follows: 1. The average time period required for the shift of phases of socialization process were; phase Ⅰ, role adjustment, took average 10 months of employment: Phase Ⅱ, interpersonal adjustment, 12 months: and Phase Ⅲ, role conflict, 15 months respectively. Conflict resolution, phase Ⅳ, began to take place 18 months of employment; and shifted to phase V, internalization and self-actualization at 25 months of employment. 2. Throughout 5 consecutive phase, the number of immediate superior nurse model was dominantly the highest among the role models. The number of head nurse role model increased at phase Ⅱ, phase Ⅲ, and phase Ⅳ. Respondents with school model in phase I tended to transfer to work model at phase Ⅱ. 3. The perceptions toward occupation were not significantly influenced by the Phases of socialization process. 4. The score of self-actualization value was not significantly influenced by the phases of socialization process. 5. In regard to perceptions toward occupation, nursing director model group showed significantly lower score in phase I (p<.01). 6. The comparison of self-actualization value between the 5 phases revealed significant difference in phase I: in particular among respondents with school model at p<.05. To conclude: 1. The phase Ⅲ of socialization process is the period of role conflict which occur at 15 months of employment, an6 conflict resolution, phase Ⅳ, begins at 18 months of employment on the average in clinical settings. 2. The immediate superior nurse and the head nurse are important role models for nurses all through their socialization process.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.146-146
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• 2000

This paper presents field test results of the GPS precise positioning using carrier phase observable. The Least-squares AMBiguity Decorrelation Adjustment(LAMBDA) method is implemented to resolve integer ambiguity problem for two epoch Ll carrier phase measurement data. Field test results show that the GPS precise positioning of cm-level accuracy is obtainable with conventional low cost, single frequency C/A code GPS receivers.