• International Journal of Precision Engineering and Manufacturing
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• 제1권1호
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• pp.111-117
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• 2000

One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric errors, thermally-induced errors, and the deterioration of the machine tools. Geometric and thermal errors of machine tools should be measured and compensated to manufacture high quality products. In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. This paper models the thermal errors for error analysis and develops an on-the-machine measurement system by which the volumetric errors are measured and compensated. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses and a designed spherical ball artifact (SBA). Experiments show that the developed system provides a high measuring accuracy, with repeatability of $\pm$2$\mu\textrm{m}$ in X, Y and Z directions. It is believed that the developed measurement system can be also applied to the machine tools with CNC controller. In addition, machining accuracy and product quality can be also improved by using the developed measurement system when the spherical ball artifact is mounted on a modular fixture.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1049-1053
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• 1999

It is important to measuring and monitoring about state vectors of power system for precise operation control. All state vectors cannot be measured because it is economically disadvantageous, so that some state vectors are determined using state estimator. Determination of observability is a important precondition of power system state estimation because state estimation can be performed when given power system is observable. Recently as time-synchronization technique progress, using the PMU(Phasor Measurement Unit), state vector can be measured directly so that voltage phasor and current phasor measurements can be used for power system estimation. In this paper, observability algorithm is proposed to determinate the observability with real/reactive injection power measurements and real/reactive lineflow power measurements of existing measurement system and with phasor measurements of PMU. The jacobian matrix is newly composed for state estimation with measurements of added PMU, and state estimation is performed with least square estimatior. Comparison between state estimation result of existing measurement system and that of measurement system added PMU is presented.

• 대한한의학회지
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• 제38권1호
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• pp.56-71
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• 2017

Objectives: The purpose of this study was to review the article using an IMU(Inertial Measurement Unit) for measuring the cervical range of motion and to evaluate the feasibility of using an IMU for measuring the cervical range of motion. Method: Scopus was used to search for the articles relating to the inclusion criteria. Which is measuring the cervical range of motion using an IMU. A total of 15 articles were selected through discussion. Degree and the reliability of the cervical range of motion and the validity of the data within the articles were extracted. Results: The measurement of the cervical range of motion using an IMU were $92.25^{\circ}$ to $138.2^{\circ}$, $122.4^{\circ}$ to $154.9^{\circ}$, $73.75^{\circ}$ to $93.1^{\circ}$ on the sagittal plane, transverse plane, and coronal plane respectively. 38 of the 43 values showed good reliability. They were larger than 0.75. 5 of the 43 values showed reliability less than 0.75. They were measured by smart phone. 16 of the 21 values showed good validity. The remaining 5 were measured by smart phone. The lower reliability and validity of smart phone were related to the protocol. The IMU can measure the coupling motion and may be used in various situations. Conclusion: The IMU may become a gold standard for measuring the cervical range of motion. The IMU measured not only the cervical range of motion but also the coupling motion. Furthermore, IMU may be used in various situations. Therefore, IMU must be considered a valuable measurement device.

• 한국정밀공학회지
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• 제16권1호통권94호
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• pp.167-173
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• 1999

This paper presents results of monitoring grinding processes with on-the-machine measurement of surface roughness by using nux ratios of scattered lights. A compact, on-the-machine surface roughness sensor. which consists of a diodelaser and several optic units. is developed. The control unit is also developed. The developed sensor together with the controller is applied for monitoring grinding processes of two different grinding machines. Experimental results show that the nux ratios and their standard deviations measured by the developed sensor over the entire ground surface are useful for monitoring grinding conditions. In particular, the sensor and the control unit are proved to be useful for monitoring grinding processes in order to detect abnormal grinding conditions and dressing time.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1992년도 추계학술대회
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• pp.89-92
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• 1992

The sensory nerve study is the important index to diagnosis peripheral neuromyotic disease. This paper discusses about the design of parameter - latency, amplitude, conduction velocity - measurement system in the sensory nerve. This system consists of three parts which are Main Control Unit(MCU), Stimulator, and external output unit. Also new measurement algorithms which is adaptive threshold method is presented in this paper. The designed system is controlled by MCU includes automatic detection algorithms and self-diagnostic functions.

• 대한의용생체공학회:의공학회지
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• 제6권2호
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• pp.33-42
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• 1985

In this paper, a mobile robot is designed for the blind guidance. This system is composed of an Ultrasonic Ranging Vnit, PWM Vnit, Optical Encoder Vnit. Specilly we adapted Distance Comparison Measurement Method (DCMM) in order to compensate for the error resulted from atmospheric conditions, and PWM unit for the vehicle control and Optical encoder unit for the correct locomotion control. This system is processed, using MCS-85 microcomputer, much of information on surrounding conduitions in real time. We rotated ultrasonic sensor for many sifted data acquisition and used tone generator for the Man-Machine Communication. As a result, the measurement error of the distance is about 1cm, the distance measurement could be detected 0.2m to 6m. The locomotion speed is 0.4m/sec and we examined its practical use.

• 산업경영시스템학회지
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• 제24권62호
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• pp.49-58
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• 2001

In recent years, a number of robot work measurement systems have been developed. This study discusses CARS (Computer Aided Romum System) which is to computerize the existed manual version ROMUM (RObot Modularization of the Unit Motion) method as the predetermined time system for robot work measurement. The ROMUM was developed to establish the standard time of work through modularize the unit motions in robot tasks. The CARS is designed on a menu driven form by computer assist for user interface and then interacts with user effectively. Therefore, the system can provide the convenience of use and minimization of analysis time and degree of judgement for establishing standard time.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.409-412
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• 2000

A high performance EEG signal measurement system is fabricated. It consists of high precision pre-amplifier and auto identification bandwidth unit. High precision pre-amplifier is composed of signal generator, signal amplifier with a impedance converter, body driver and isolation amplifier. The pre-amplifier is designed for low noise characteristics, high CMRR, high input impedance, high IMRR and safety, Auto identification bandwidth unit is composed of AD-converter and PIC micro-controller for real time processing EEG signal. The performance of EEG signal measurement system has been shown the classified bandwidth through the clinical demonstrations.

• 대한간호학회지
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• 제22권4호
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• pp.589-603
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• 1992

This study investigated a process to estimate the need for nursing staff on the basis of a patient elassification system and the required care needs and activities. The investigation was carried out in the following four steps. Step 1. Patients were classified according to the amount of nursing care need on each shift as class I (mildly ill), class II (mederately ill), class III (acutely ill), and class IV (critically ill). Step 2. Measurement of the direct nursing care hours needed for each patient class, and measurement of indirect nursing care hourse and personal time of the nursing staff. Step 3. Calculation of he total nursing workload in a nursing unit. Step 4. Estimation of the nursing staff needed. The investigation was carried out from July 17th to 30th, during 24hours every other day. The subjects were the patients and the nursing staff on two units of Seoul National University Hospital, Korea. Some of the results from the investigation are as follows : 1) Distribution of patient classification On the neuro surgical (N.S.), the distribution was class I, 22 patient, 3, class II, 27 patients, class III, 26 patients, and class IV, 25 patients, For the orthopedic surgical unit(0.5.), it was class I, 43 patients, class II, 43 patients, class III, patients, and class IV, 3 patients. 2) Direct nursing care hours per day On the N.S. unit, 3.2 hours of direct nursing care were needed for class I, 3.9 hours for class II, 5.1 hours of class III, and 6.2 hours for class IV patients, while 2.0 hours for class I, 2.5 hours for class II, 3.5 hours for class III, 5.0 hours class IV patients were needed on the 0.5. units. 3) Analysis of direct nursing care activities Activities were classified into assessment and observation(47%), medication(38.7%), communiontion(5.1%), exercise(2.4%), elimination and irrigation(1.3%), treatmemt(1.1%), hygiene(0.8%), nutrition(0.8%), and hot and cold compress(0.1%). 4) Average hours of indirect nursing care per day. On the N.S. unit 4.2 hours, and on the O.S. unit, 3.5 hours of RN indirect care was needed. 5) The average personal time used by the of nursing staff was 17 minutes for both RNs and nursing assistants in the N.S. unit, and 32 minutes for both RNs and nursing assistants in the O.S. unit. 6) Estimation of nursing staff needed on two specialized units of a university hospital For the N.S. nursing unit of 43 beds, 31 nursing staff would be indicated. For the 0.5. nursing unit of the same number of beds, 19 nursing staff would be indicated.

• 한국안전학회지
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• 제15권4호
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• pp.157-162
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• 2000

A performance measurement system for safety management was suggested with which performance of a company's safety activities can be expressed rationally, and analysis of impact with performance improvement. A key of the measurement system is performance index of the safety management activities, which consists of 3 perspectives; an external perspective, an internal perspective, and a innovation & learning perspective. Every perspective consists of 18 performance indices and each indices consist of activity unit a such planning, support, implementation, evaluation and review.