• 한국신뢰성학회지:신뢰성응용연구
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• 제15권1호
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• pp.27-32
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• 2015

Functional safety is part of the overall safety relating to the equipment under control (EUC) and the EUC control system that depends on the correct functioning of the electrical/electronic/programmable electronic (E/E/PE) safety-related systems. Since the complexity of the medical equipment is increased, manufactures have to obtain functional safety as well as basic safety. This study proposes a perspective for applying functional safety to medical equipment. The research is carried out with respect to overall safety life-cycle of functional safety and essential performance of the medical equipment. The relationship between functional safety and essential performance is identified centered on the safety function. The essential performance using E/E/PE systems is defined as a safety function of functional safety. This approach is applied to a ultrasound imaging system as a case study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.48-50
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• 2005

New environment change of electric power system focused in consumer's energy supply and demand. But electric power reliability preservation and reliability improvement countermeasure also need for long-term. It is need that change equipments that is composing electric power system in well-timed time and by maintaining, prevent breakdown beforehand and prevent consumer's power interruption by equipment fail. However, as only quantitative estimation is available by reliability estimation method that is presented in existing, it is no to use in dictionary fault prevention. Therefore, applied optimum reliability preservation through existent equipment fault data analysis of electric power system in equipment replace side, and this when maintain equipment replace of electric power system for reliability preservation using responsiveness analysis to base ordering evaluate. In existing about main equipment plain that this paper is power system the valued failure rate use this by score and precedence of electric power system equipment for replace of system considered expense.

• 한국식생활문화학회지
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• 제10권1호
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• pp.1-10
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• 1995

The purpose of this study is to identify potentially hazardous factors which can contribute to the outbreak of food borne disease and present more practical management methods in terms of sanitary management of cooking equipment and personal hygiene. 230 Korean-style restaurants in Seoul were surveyed in the same manner on the published study-A study for the Improvement of Sanitary Condition in Korean style-restaurant in Seoul city area (I). Sanitary check-lists were developed to evaluate the sanitary status of cooking equipment and personal hygiene of employee. The sanitary condition of cooking equipment the maintenance of refrigeration, food habits and personal hygiene were assessed by the sanitary score. The sanitary condition of cooking equipment, the maintenance of refrigeration as well as food habits and personal hygiene employee was in good condition. The effective sanitation education and training for good service workers should be practice for the improvement of sanitary management of cooking equipment and personal hygiene.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1858-1868
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• 2021

Resisting an accidental impact of large commercial aircrafts is an important aspect of advanced nuclear power plant (NPP) design. Especially after the 9·11 event, some regulations were enacted, which required the design of NPPs should consider the accidental impact of large commercial aircrafts. Normal working of equipment is important for stopping reactor under an impact when an NPP is in operation. However, there is a lack of reliable analysis and research on the impact test of nuclear prototype equipment. Therefore, in order to study the response of the equipment under high acceleration impact, a centrifugal pump is selected as the research object to perform the impact test. A horizontal half-sinusoidal pulse wave was applied to the working pump. The test results show that the horizontal response of the motor and flange is greater compared to other parts, as well as the vertical response of the coupling. The stress response of the pump body support and motor support is high, hence these parts should be considered in the design of the pump. Finally, combined with the damage and stress evaluation results of the pump under different amplitudes, the ultimate impact acceleration that the pump can withstand is given.

• 전기학회논문지
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• 제63권4호
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• pp.589-595
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• 2014

The error of instrument transformers is measured by connecting the external burden with the secondary terminal of the instrument transformers. Because the error of transformer is affected by the apparent power and power factor of the external burden, an accurate measurement of burden is important for transformer evaluation. We have developed the burden evaluation equipment for both potential transformer and current transformer by employing the series resistor in the range of $20m{\Omega}{\sim}5{\Omega}$ and the parallel resistor in the range of $1M{\Omega}{\sim}500{\Omega}$, respectively, together with visual basic program. We could reduce testing time more than 5 times by employing method developed in this study, compared with that developed in past. This method shows more better reliability by analyzing the evaluation results and fitting graphs of burden measurements. The test results of the developed system is compared with those obtained in the power meter analyzer to verify the validity.

• 자동차안전학회지
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• 제12권3호
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• pp.43-51
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• 2020

Currently, the second level of the six stages of self-driving technology, as defined by SAE, is commercialized, and the third level is preparing for commercialization. The purpose of ACC is to be evaluated as a system useful for preventing and preventing accidents by minimizing driver fatigue through longitudinal speed control and relative distance control of the vehicle. In this regard, for the study of safety assessment methods in the practical environment of ACC. Distance measurement method using monocular camera and data acquisition equipment such as DGPS are utilized. Based on the evaluation scenario considering the domestic road environment proposed by the preceding study, the relative distance obtained from equipment such as DPGS and the relative distance using a monocular camera in the actual test is verified by comparing and analyzing the safety assessment. The comparison by scenario results showed a minimum error rate of 3.83% in Scenario 1 and a maximum of 14.61% in Scenario 6. The cause of the maximum error is that the lane recognition is not accurate in the camera image and irregular operation conditions such as rushing in or exiting the surrounding area from the walkway. It is expected that safety evaluation using a monocular camera will be possible for other ADAS systems in the future.

• 한국도로학회논문집
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• 제8권3호
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• pp.21-28
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• 2006

Field or laboratory wheel tracking tests have been employed for the evaluation of the rutting potential of asphalt paving mixtures. Compared to field tests, laboratory wheel tracking tests are much less expensive and more manageable for most road projects. However, most test laboratories are not equipped to perform such tests because there does not exist any standard test procedure, and the required equipment is rather expensive. Futhermore, the size of test specimens and the relatively large quantity of test mixture required present difficulties for laboratory specimen mixing and compaction. This paper describes a project conducted to study the feasibility of replacing wheel tracking testsby a repeated-load creep test for rutting potential evaluation. Comparisons were made between the results of the two tests for different test temperatures, loading speeds and applied pressures. Three types of asphalt mixtures were studied in the test program. Favorable conclusions concerning the use of the repeated-load test for rutting potential evaluation were drawn based on the findings of the experimental test results. The correlation between the two types of tests was found to be good for all threeasphalt mixtures. Adopting the repeated-load creep test would lead to cost savings since it employs standard test equipment already available in most laboratories. It would also result in substantial time savings due to the much smaller quantity of mix needed, and the ease in specimen preparation.

• 대한조선학회논문집
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• 제47권6호
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• pp.808-812
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• 2010

This paper studies the finite element modeling and analytical parameters for the numerical evaluation of dynamic stiffness of large foundation for shipboard equipments such as marine diesel engine. For the purpose, numerical method and procedure to evaluate the dynamic stiffness are established based on the impact test method, which are applied for the dynamic stiffness evaluation of a real diesel generator foundation of ship. Numerical investigations compared with the measured data are carried out to evaluate the effects of modeling ranges of ship substructure, finite element sizes, lower support structures and damping coefficients. From the results, modeling and analytical parameters for proper evaluation of dynamic stiffness of large foundation of shipboard equipment are suggested.

• 반도체디스플레이기술학회지
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• 제20권1호
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• pp.25-31
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• 2021

The semiconductor and display equipment demands an ultra-fine precision of several nm to several ㎛, and the scale is getting smaller due to the explosive development. The manufacturing process equipment for such products with ultra-fine precision is very sensitive to ultra-small vibrations flowing from the floor, resulting in problems of production defects and yield degradation. The vibration criteria are a standard that regulates the vibration environment of the floor where such precision process equipment will be installed. The BBN vibration criteria defined the allowable vibration velocity level in the frequency domain with a flat and inclined line and presented a rating according to it. However, the actual vibration criteria have appeared with various magnitudes in the frequency domain according to the dynamic characteristics of individual equipment. In this study, the relationship between the relative motion of two major points in the equipment and the vibration magnitude of the floor is presented using the frequency response function of a simple 3-DOF model. It is describing the magnitudes according to the frequency of the floor vibration that guarantees the allowable relative motion and this can be used as the vibration criteria. In order to obtain the vibration criteria experimentally a method of extracting through a modal test was introduced and verified analytically. It provides vulnerable frequency and magnitude to floor vibration in consideration of the dynamic characteristics of individual equipment. And it is possible to know necessary to improve the dynamic characteristics of the equipment, and it can be used to check the vibration compatibility of the place where the equipment will be installed.

• 한국응급구조학회지
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• 제24권3호
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• pp.41-53
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• 2020

Purpose: This study tests the validity of a standard evaluation tool of ambulance ride practices with new evaluation items and supports its application by 119 preceptors. Methods: We tested the validity of standard evaluation items collected from 19 on-site professionals assessing ambulance ride practices. New evaluation items, 'understanding of emergency rescue equipment' and 'ability to communicate', were added as additional criteria. The modified Delphi technique was used to test the three evaluation areas and ten evaluation items. We used the analytic hierarchy process to analyze the weighting value of the reconstructed evaluation tool model. Results: All three evaluation areas and 10 evaluation items within the standard evaluation tools used for ambulance ride practices corresponded with the consistency index, degree of convergence, and agreement in the modified Delphi panel. Conclusion: These results provide evidence of the consistency and usefulness behind preceptors' use of this standard evaluation tool in ambulance ride practice.