• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.199-206
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• 2019

Recently, an expansion of safety facilities has been widely applied to effectively manage the safety of train operation due to increase of the high-speed section of the general railway and the introduction of high-speed train. Accordingly, performance improvement, upgrading and high reliability of existing safety devices are required. the dragging detector, one of the safety devices, is an analogue system that consists of closed circuit with an electric current flows and operates when the closed circuit is opened by the impact of the dragging object. Such method has unreasonable problem that should be replaced after being detected. It is need to replace with an automatic return type dragging detector which is easy to maintain. In addition, it is necessary to develop a dragging detector that applicable to general railway and urban railway including high-speed railway, in accordance with the speeding up and densification of trains, although it is currently applied only to high-speed railway. In this paper, we propose an automatic return type dragging detector which has versatility and excellent maintainability with digital sensor and real time monitoring.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.2
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• pp.49-55
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• 2006

In the consideration of the problem occurred by certain return bender brazing welding works that depend only on handworks, the automatization of the whole production line is impossible due to the high dependency of skillful workers. In addition, it is difficult to establish a standardization due to the various heat exchanger model and irregular amount of orders, and the fault reduction is also impossible due to the severe difference in brazing conditions. It is necessary to develop a method, which quantitively analyzes the problem existed in this manual brazing welding of return benders and technically solves that problem, and to lead the improvement of the productivity and cost reduction in order to increase the business competitive power. Then, this will contribute the technical development of automatic welding for Korea's heat exchanger businesses. Thus, this study develops an automatic technology, which automatically controls the flame strength using digital control methods, for various models and produces a sample model. It is possible to increase the productivity and produce uniformed and qualified products by solving the problem existed in manual processes using the developed automatic return bender brazing system. In addition, the brazing condition can be automatically controlled according to the model and line speed, and such an economical operation can reduce the production cost. The developed system is expected to future applications not only heat exchangers in the field of refrigeration and air conditioning, but also other various industrial fields that apply heat exchangers, such as car and boiler industries.

• Journal of the Korean housing association
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• v.13 no.6
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• pp.89-99
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• 2002

The purpose of this research is to analyze the characteristics of flow rate distribution in hot-water piping networks in the apartment building. A 14-story apartment house was selected as a sample building and analyzed numerically by Hardy-Cross method. Two different piping networks, one has three vertical zones and the other of a single zone with automatic balancing valves, were compared. Some of research results are as follows; As the temperature of supply hot-water increases, the flow rate of it does by buoyancy effect, but this effect is not found in the piping network with automatic balancing valves. Non-uniformity in hot-water flow distributions to all stories in the piping system of single vertical zone can be completely reformed by the installation of either manually operated or automatic balancing valves in every story.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.5
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• pp.109-120
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• 2017

It is important to estimate objectively in the driving test. Especially, the driving test is examined by totally driving ability, rule observation and situational judgement. For this, a grading automation system for driving test was presented by using GPS, sensor data and equipment operation informations. This system is composed of vehicle mounted module, automatic grading terminal, data controller, data storage and processing server. The vehicle mounted module gathters sensor data in the car. The terminal performs automatic grading using the received sensor data according the driving test criterion. To overcome the misposition of vehicle in the map due to GPS error, we proposed the automatic grading system by map matching method, path deviation and return algorithm. In the experimental results, it was possible to grade automatically, display the right position of the car, and return to the right path under 10 seconds when the vehicle was out of the shadow region of the GPS. This system can be also applied to the driving education.

• Current Research on Agriculture and Life Sciences
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• v.32 no.3
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• pp.165-169
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• 2014

This study assessed the economic feasibility of an automatic egg washer. Based on various cost benefit analysis methods, including the net present value (NPV), internal rate of return (IRR) and benefit cost ratio (B/C Ratio), the automatic egg washer was confirmed to have economic feasibility. The NPVs were 38,565,991 won at 5% discount rate and 32,013,916 won at 10% discount rate, respectively. The IRRs were 1.325 at 5% discount rate and 1.299 at 10% discount rate, respectively. Finally, the B/C ratios were 1.726 at 5% discount rate and 1.699 at 10% discount rate.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.2
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• pp.181-187
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• 2023

Laver aquaculture, which occupies a large proportion in the aquaculture industry in Korea, is still highly dependent on human labor. Therefore, it is necessary to study the development of an automatic system to improve the working environment and increase the efficiency of aquaculture production systems. The purpose of this study is to evaluate the economic feasibility of an improved system in a study for the loading-unloading and automatic weighing systems in laver aquaculture industry. Economic analysis of the developed unloading and automatic weighing system were implemented under various conditions to calculate more accurate benefits and costs. As a result of this study, the economic feasibility was found to be very high in the three models: net present value (NPV), benefit-cost ratio (B/C), internal rate of return (IRR). Moreover, the results of sensitivity analysis showed that the economical efficiency of the automatic loading, unloading, and weighing system in laver aquaculture was very high.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1209-1214
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• 2009

Various automatic temperature control systems have been used widely in Korea for the conservation of heating energy and the enhancement of thermal comfort in residential buildings. But the heating control performance for automatic temperature control systems extensively vary with the design and operational conditions of the heating system, the climate condition and others. It was introduced in this study a numerical calculation program package to analyze heating control characteristics of the automatic temperature control system. This package is able to analyze the room air temperature, return water temperature, supplied heating flux and flow rate, and so on. One the other hand, the simulation results were verified by comparing with the field test results.

• Journal of Chest Surgery
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• v.28 no.6
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• pp.542-548
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• 1995

The goal of this study is to develop an effective control system for cardiac output regulation based upon the preload and afterload conditions without any transducers and compliance chambers in the moving actuator type total artificial heart. Motor current waveforms during the actuator movement are used as an input to the automatic control algorithm. While the current waveform analysis is performed, the stroke length and velocity of the actuator are gradually increased up to the maximum pump output level. If the diastolic filling rate of either right or left pump begins to exceed the venous return, atrial collapse will occur. Since the diastolic suction acts as a load to the motor, this critical condition can be detected by analyzing the motor current waveforms. Every time this detection criterion is met, the control algorithm decreases the stroke velocity and length of the actuator step by step just below the critical detection level. Then, they start to increase. In this way the maximum pump output under given venous return can be achieved. Additionally the control algorithm provides some degree of afterload sensitivity. If the aortic pressure is detected to exceed 120 mmHg, the stroke length and velocity decrease in the same way as the response to the preload. Left-right pump output balance is maintained by proper adjustment of the asymmetry of the stroke angle. In the mock circulatory test, this control system worked well and there was a considerable range of stroke volume difference with adjustment of the asymmetry value. Two ovine experiments were performed. It was confirmed that the required cardiac output regulation according to the venous return could be achieved with adequate detection of diastolic function, at least in the in vivo short-term survival cases[2-3 days . We conclude that this control algorithm is a promising method to regulate cardiac output in the moving actuator type total artificial heart.

• Current Research on Agriculture and Life Sciences
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• v.32 no.4
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• pp.231-235
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• 2014

This study performed a benefit cost analysis of an automatic eggshell crack detection system. Based on various cost benefit analysis methods, including the net present value (NPV), internal rate of return (IRR), and benefit cost ratio (B/C Ratio), the automatic eggshell crack detection system was confirmed to have economic validity. The NPVs were 175,035,645 won at a 5% discount rate and 129,082,393 won at a 10% discount rate. Plus, the IRRs were 0.686 at a 5% discount rate and 0.660 at a 10% discount rate. Finally, the B/C ratios were 1.981 at a 5% discount rate and 1.900 at a 10% discount rate.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.16
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• pp.7-34
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• 2001

This Study analyzes the fact that whether or not, the applicant, by failing to object promptly to the facial discrepancies of the presented documents and to return those documents to the issuing bank, has waived his right to sue for breach of the Application agreement based on the recent Korea-US Case law. Some commentators claim that an applicant has a duty to notify the issuing bank within a reasonable time after receiving the documents that they do not comply with the letter of credit requirements and to return those documents to the issuing bank, and also suggest that a failure to do so result in a waiver of discrepancies that operates as a matter of law. But such decisions make little sense in letter of credit transaction. Unless otherwise agreed, Applicant agreement does not require that the applicant notify the issuing bank of any facial discrepancies of the documents or return those documents. Moreover there is no support in the body of law, i.e., UCP 500 or the Revised UCC Article 5, for an automatic waiver or preclusion arising from the applicant's failure to object promptly. In addition, beyond the lack of authority to support an automatic waiver arising from the applicant's failure to object and return the documents, in a letter of credit transaction the issuing bank is the only party charged with the duty of scrutinizing documents. Therefore, if there are discrepancies, it is the bank that should have to seek an express waiver from the applicant ; the issuing bank should not avoid responsibility for failing to notice discrepancies because the applicant was slow to scrutinize the documents closely or because the applicant failed to inform the issuing bank of such discrepancies. Requiring that applicants inspect documents independently defeats the purpose of retaining the issuing bank, erodes the bank's responsibility to perform its role diligently, and may result in the bank avoiding liability despite negligent payment. If the bank wants to require an applicant to report discrepancies promptly, he may include a provision in the Application agreement limiting the time limit within which the applicant must give notice of facial discrepancies and return the documents. This approach will ensure the continued wide-spread use of documentary credit as a reliable payment mechanism.