• Earthquakes and Structures
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• v.15 no.1
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• pp.81-95
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• 2018

Most buildings feature core walls (and shear walls) that are placed eccentrically within the building to fulfil architectural requirements. Contemporary earthquake design standards require three dimensional (3D) dynamic analysis to be undertaken to analyse the imposed seismic actions on this type of buildings. A static method of analysis is always appealing to design practitioners because results from the analysis can always be evaluated independently by manual calculation techniques for quality control purposes. However, the equivalent static analysis method (also known as the lateral load method) which involves application of an equivalent static load at a certain distance from the center of mass of the buildings can generate results that contradict with results from dynamic analysis. In this paper the Generalised Force Method of analysis has been introduced for multi-storey buildings. Algebraic expressions have been derived to provide estimates for the edge displacement ratio taking into account the effects of dynamic torsional actions. The Generalised Force Method which is based on static principles has been shown to be able to make accurate estimates of torsional actions in seismic conditions. The method is illustrated by examples of two multi-storey buildings. Importantly, the black box syndrome of a 3D dynamic analysis of the building can be circumvented.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.4
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• pp.301-307
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• 2013

MRU(motor reduction unit) for KTX is a assembled complex structure that is equipped with a lot of parts at the express train KTX and that is the core power source operating variable speeds. This study is recorded the dynamic characteristics analysis results tested by EMA which is done through the parts and assembly test, transient analysis and stoped train test in order to design the online monitoring system for KTX MRU. And the mode shapes result from critical vibration frequency explain the relation with variable speeds of express train over 250 km/hr. Also these variable speeds make variable operational frequencies at pinion, axle gear mesh frequency and normal bearing fault frequencies. As the specified speed can make resonance with natural frequencies of the MRU, for the train operating stability, this study also presents the MRU's critical speeds calculated by the each train speed.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.344-345
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• 2011

A necessity to a superconducting cable in power transmission systems have been growing more and more due to high power density in urban areas and rapid increase of power demand. In view of these situation, it is a noteworthy fact that superconducting cable has remarkable advantages, such as lower power loss and 3-5 times higher power transmission capacity, compared with conventional power cable. For the last a few years, long-term reliability tests had been carried out in the KEPCO PT Center, and now it has been installed in KEPCO's real power grid for demonstrating commercial operation. This paper deals with the test results of dielectric properties performed at manufacturing factory for the joint box, termination and core of HTS cable system and whole system connected in real power grid.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.283-292
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• 2020

Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.2016-2034
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• 2011

Ubiquitous Healthcare (u-Healthcare) is the intelligent delivery of healthcare services to users anytime and anywhere. To provide robust healthcare services, recognition of patient daily life activities is required. Context information in combination with user real-time daily life activities can help in the provision of more personalized services, service suggestions, and changes in system behavior based on user profile for better healthcare services. In this paper, we focus on the intelligent manipulation of activities using the Context-aware Activity Manipulation Engine (CAME) core of the Human Activity Recognition Engine (HARE). The activities are recognized using video-based, wearable sensor-based, and location-based activity recognition engines. An ontology-based activity fusion with subject profile information for personalized system response is achieved. CAME receives real-time low level activities and infers higher level activities, situation analysis, personalized service suggestions, and makes appropriate decisions. A two-phase filtering technique is applied for intelligent processing of information (represented in ontology) and making appropriate decisions based on rules (incorporating expert knowledge). The experimental results for intelligent processing of activity information showed relatively better accuracy. Moreover, CAME is extended with activity filters and T-Box inference that resulted in better accuracy and response time in comparison to initial results of CAME.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.413-416
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• 2006

In process of the mass concrete structure, the heat of hydration may cause serious thermal cracking. In order to eliminate hydration heat of mass concrete, this paper reports results of hydration heat control of mass concrete using the Oscillating Capillary tube Heat Pipe(OCHP). There were the several RC box molds which shows a difference as compared with each other. One was not equipped with OCHP. The others were equipped with OCHP. All of them were cooled with natural air convection. The OCHP was composed of copper pipe with 11 turns(outer diameter : 4mm, inner diameter : 2.8mm) and heat type was non-looped type. The working fluid was R-22 and its charging ratio was 40% by volume. The core of the concrete temperature was approximately $55^{\circ}C$ in the winter without OCHP. But the concrete temperature with OCHP was reduced its difference in temperature with the outdoor temperature to $12^{\circ}C$. Finally we saw the index figure of the thermal crack of the structures were varied from 0.75 to 1.47.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.361-366
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• 2001

A mim turbo-shaft engine of 50HP for UAV, which can be easily modified to turbo-prop and turbo-jet engine by sharing the core engine and has many applications to civilian demands and munitions, will be developed This kind of micro gas turbine engine has been developed mostly by the corporations which have special technology but are small in its scale. Especially, the gas turbine engine can be easily applied to other fields and developed by domestic technology, so that the sharing of technology is planed to realize through the cooperations with academies and research institutes. In this paper, the gas turbine engine, which has the compressor ratio of 3.8, the turbine inlet temperature of l180K and the engine speed higher than 100,000 rpm, is composed of centrifugal compressor, combustor, gas generator turbine, free power turbine and gear box. The competitiveness of the gas turbine engine can be obtained from minimizing its cost by the utilization of domestic infrastructure for the performance test and the decisive outsourcing.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.667-672
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• 2005

The uncemented breccia consisted of conglomerate and breccia, which are not originated from volcanic clastics, shows wide variation of engineering properties depending on the characteristics of matrix of the uncemented breccia. These uncemented breccia have breccia and matrix irregularly distributed according to their depth and position. Clay minerals are also included in the matrix of these uncemented breccia, so they are expected to show expansive behavior and weakness against weathering process. In this study, the volumetric ratio of breccia on the cores had been calculated using digital image processing technique (performed on recovered core box and their sections). The 3-axial compressional strength test had been done with a shaping of rapid cooling method, and the shear strength (c, ${\phi}$) of uncemented breccia due to the breccia content had been calculated by applying BIMROCK model curve suggested by Goodman. A reliable analysis on the engineering properties of uncemented breccia had been also possible by using borehole density logging and borehole loading test for the accurate determination of the unit weight and the deformation constants deformation modulus.

• Nuclear Engineering and Technology
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• v.27 no.6
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• pp.870-876
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• 1995

In this paper, a new three-dimensional nodal diffusion code which is based on the AFEN methodology is described and tested. The method expands the homogeneous flux within a node in ter-ms of eighteen analytic basis functions satisfying the diffusion equation at any point of the node. And the nodal coupling equations are derived such that nodal balance, current continuity and leakage balance within an infinitesimally small box around the edge are satisfied. To verify its accuracy, the code was applied to the well-known static LMW benchmark problem and a small core benchmark problem that has the same material properties as the three-dimensional IAEA benchmark problem and compared with two other codes (QUANDRY, VENTURE). The results show that the code provides good accuracy both in the power distribution and in the effective multiplication factor.

• Journal of the Korean Ceramic Society
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• v.49 no.2
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• pp.161-166
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• 2012

The temperature-rasing sintering method was used in this study to fabricate the aggregates of uniform pore size and distribution containing reject ash occurred in the thermal power plant. The spheric green aggregates made of reject ash were put into the box furnace of 800~$1000^{\circ}C$, heated with a heating rate of 5~$15^{\circ}C$/min to 1200~$1275^{\circ}C$, sintered for 10 min and then discharged out of the furnace to the room temperature. The input temperature, heating rate and sintering temperature increased the bloating phenomenon of the specimen, and the sintering temperature among them was the most effective factor. The aggregate manufactured at $1275^{\circ}C$ had the specific gravity of about 1.0 and water absorption of 1~2%, and the pores of 500~1,000 ${\mu}m$ were uniformly distributed across the whole specimen. Especially, the aggregates fabricated using the temperature-rasing sintering method in this study showed an excellent bloating properties and uniform microstructure without black core phenomenon which is typical for the bloated ceramics synthesized by direct sintering method.