• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1252-1256
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• 2016

Internet of Things(IoT)-devices are now expanding inter-connecting networking technologies to invent healthcare monitoring system especially for assessing physiological conditions of the chronically-ill patients those with cardiovascular diseases. Hence, IoT system is expected to be utilized for home healthcare by dedicating the original usage of IoT devices to collect the biomedical data such as electrocardiogram(ECG) and photoplethysmography(PPG) signal. The aim of this work is to implement health monitoring system by integrating IoT devices with Raspberry-pi components to measure and analyze ECG and the multi-channel PPG signals. The acquired data and fiducial features from our system can be transmitted to mobile devices via wireless networking technology to support the concept of tele-monitoring services based on IoT devices.

• Journal of Power Electronics
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• v.12 no.1
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• pp.104-112
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• 2012

In this paper a new method for the design of a simple PI controller is presented and it has been applied in the control of a Boost based PFC rectifier. The Strength Pareto evolutionary algorithm, which is based on the Pareto Optimality concept, used in Game theory literature is implemented as a multi-objective optimization approach to gain a good transient response and a high quality input current. In the proposed method, the input current harmonics and the dynamic response have been assumed as objective functions, while the PI controller's gains of the PFC rectifier (Kpi, Tpi) are design variables. The proposed algorithm generates a set of optimal gains called a Pareto Set corresponding to a Pareto Front, which is a set of optimal results for the objective functions. All of the Pareto Front points are optimum, but according to the design priority objective function, each one can be selected. Simulation and experimental results are presented to prove the superiority of the proposed design methodology over other methods.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1535-1547
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• 2016

This paper proposes various design procedures for computing Power System Ancillary Service Requirement Assessment Indices (PSASRAI) for a Two-Area Thermal Reheat Interconnected Power System (TATRIPS) in a restructured environment. In an interconnected power system, a sudden load perturbation in any area causes the deviation of frequencies of all the areas and also in the tie-line powers. This has to be corrected to ensure the generation and distribution of electric power companies to ensure good quality. A simple Proportional and Integral (PI) controllers have wide usages in controlling the Load Frequency Control (LFC) problems. So the design of the PI controller gains for the restructured power system are obtained using Bacterial Foraging Optimization (BFO) algorithm. From the simulation results, the PSASRAI are calculated based on the settling time and peak over shoot concept of control input deviations of each area for different possible transactions. These Indices are useful for system operator to prepare the power system restoration plans. Moreover, the LFC loop coordinated with Redox Flow Batteries (RFB) has greatly improved the dynamic response and it reduces the control input requirements and to ensure improved PSASRAI, thereby improving the system reliability.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.5
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• pp.565-572
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• 2002

The design concept of diesel engines for sea-going ships has been directed to Low-speed/Long-Stroke type to improve the efficiencies of combustion and propelling. But time-delay inevitable at low speed gives much difficulties for governors to control the engine speed because they would be apt to go into unstable region especially when operating at low speed. The purpose of this paper is to study the problem of how the governor gain can be calculated dynamically in accordance with the valiance of engine speed to locate the engine still on the properly stable condition. In this study, the property of diesel engine was described as composed of combustion element including dead time and rotating element, and the ultimate gain for the speed control system to be located on the condition of stability limit was proposed based on the frequency characteristics. And the target gains with optimized stability also were proposed by giving proper margin to these ultimate conditions. The results were applied to a model system and the availability was confirmed to be satisfactory.

• Journal for History of Mathematics
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• v.19 no.3
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• pp.95-112
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• 2006

The purpose of this paper is to investigate a classic mathematician and inventor Archimedes' work ${\ll}$On the Sphere and Cylinder${\gg}$. The propositions of this book which deals with three dimensional geometry are reviewed. Through the review this study tries to find out how Archimedes mastered spherical figures and how classical mathematics ideas are related to the modern concept of integration. The results of this study seems to help people understand deeply modern mathematics and to be good resources to develop new mathematical ideas.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.17-24
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• 1992

It would be much effective that single column type pier is used in concrete slab bridges rather than ${\Pi}$ or gravity type pire is used. To determine the longitudinal benging moment in concrete slab bridges supported by single column type piers, the concept of effective width is applied. By elastic plate theory cooperated with finite element method, the distribution of the longitudinal moment of the slab supported by single column type piers is studied. The main variables are span, width. thickness of the slab, and column section size. The analytical results obtained are summarized and analysed to evaluate the maximum longitudinal negative moment, then a simplified method for calculating the longitudinal moment is proposed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.2
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• pp.13-23
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• 2016

Many traffic centers are highly hesitant in employing existing Automatic Incident Detection Algorithms due to high false alarm rate, low detection rate, and enormous effort taken in maintaining algorithm parameters, together with complex algorithm structure and filtering/smoothing process. Concerns grow over the situation particularly in Freeway Incident Management Area This study proposes a new algorithm and introduces a novel concept, the Displaced Flow Index (DiFI) which is similar to a product of relative speed and relative occupancy for every execution period. The algorithm structure is very simple, also easy to understand with minimum parameters, and could use raw data without any additional pre-processing. To evaluate the performance of the DiFI algorithm, validation test on the algorithm has been conducted using detector data taken from Naebu Expressway in Seoul and following transferability tests with Gyeongbu Expressway detector data. Performance test has utilized many indices such as DR, FAR, MTTD (Mean Time To Detect), CR (Classification Rate), CI (Composite Index) and PI (Performance Index). It was found that the DR is up to 100%, the MTTD is a little over 1.0 minutes, and the FAR is as low as 2.99%. This newly designed algorithm seems promising and outperformed SAO and most popular AIDAs such as APID and DELOS, and showed the best performance in every category.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.33-40
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• 2012

Objective: Service industry has become the most important industry among various economic activities, as the percentage of service related industry in advanced nations is over 60% of their GDP and the percentage of service industry in South Korea, a traditional manufacturing nation, now takes up over 60% of the entire economy. Background: Such industry paradigm shift has changed consumers from those that simply purchased products into groups of people that evaluate the companies that manufacture products, thereby further intensifying competition among companies and increasing the importance of integrated communication between companies and consumers. However, the excessive existence of sub-identities that have been developed for integrated management of the existing corporate identities, as well as the undifferentiated general management strategies by companies are creating confusion not only for consumers but also for various corporate interest parties. In addition, service identity strategy has become the most important strategy than any other sub-identity strategies in forming corporate identity at the increased importance of corporate service in the era of service industry. However, the current domestic circumstance is that the concept of service identity has not been well established through specific related studies. Method: Accordingly, the existing academic and field studies on the corporate identity(CI), brand identity(BI) and product identity(PI) used for the communication with consumers were reviewed in this study to establish and summarize the concept of service identity(SI) that appeared at the service economization. Results: The purpose is to examine the kind of change that could be brought about by SI for the corporate integrated identity strategy developed through the existing corporate, brand & product image in order to present a new direct in corporate identity strategy according to the industry paradigm shift through a SI centered new corporate identity framework. Conclusion: For preparing the new era of service industry, the corporate integrated identity strategy must be integrate with concept of service identity and which is essential to differential from other companies. Application: The proposed concept and framework of service identity on this paper will help to understand and clearly define why service identity is important factor of the new idea of corporate identities.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.1
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• pp.1-9
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• 1985

In-plane tension fatigue tests (R = 0.05) were carried out to investigate the initiation and propagation behaviors of micro-surface-fatigue cracks on smooth surfaces of a mild steel. Also, the investigations of saturated cyclic strain which can be obtained by the fatigue tests have been made via the cyclic strain intensity factor, .DELTA. $K_{\epsilon}$/, for the purpose of unifying two approaches of the study of fatigue; the one approach is based on the fracture mechanics concept and the other on lowcycle fatigue concept. Some of the results are as follows; The growth rate, d(2a)/dN, of small cracks cannot be represented by one straight line as a function of .DELTA.K for various of the nominal stress range, .DELTA..sigma., and is higher than that of a larger through crack. The rearrangement of the d(2a)/dN by .DELTA..epsilon..root..pi.s( = .DELTA. $K_{\epsilon}$/) with the stress range .DELTA..epsilon. in .DELTA.K replaced by .DELTA..epsilon., strain range, gives one straight line of the .DELTA. $K_{\epsilon}$-d(2a)/dN relation for various values of stress range .DELTA.$_{\epsilon}$../.X>../.

• Clean Technology
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• v.1 no.1
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• pp.34-46
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• 1995

Clean Technology goes beyond Clean-UP (or "End of PiPe) Technologies to include Pollution prevention, waste minimisation, and cleaner production. However, the concept of Clean Technology goes deeper than changes in technology, to ways in which human needs can be satisfied sustainably. In other words, Clean Technology, concentrates on delivering a human benefit rather than making a product. Introducing cleaner technology may therefore involve new commercial relationships as well as new technological practices. In some economic sectors, this involves leasing or providing a service rather than selling a product. Life Cycle Assessment (LCA) is an important tool in Clean Technology. LCA involves determining all the resources used and all the wastes and emissions produced in providing the human benefit. Use of LCA ensures that improved environmental performance in one part of the Life Cycle is not achieved merely at the expense of more environmental damage elsewhere. Going beyond LCA, the concepts of Life Cycle Design and "metabolised" use of materials are approaches to obtain maximum benefit from materials as they pass through the human economy. "Closed-loop" use can be a component of clean technology. Looking beyond simple re-use and recycling, a material may pass through a "cascade of uses". typically a series of applications with progressively lower performance specifications. Closed-loop use necessarily involves a change in commercial practice, because the material or product must be recovered after use.