• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.275-282
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• 2013

Applications such as vibration isolation, gravity compensation, pick-and-place machines, etc., would benefit from (long-stroke) cylindrical/tubular permanent magnet (PM) actuators with integrated passive gravity compensation to minimize the power consumption. As an example, in component placing (pick-and-place) machines on printed circuit boards, passive devices allow the powerless counteraction of translator including nozzles or tooling bits. In these applications, an increasing demand is arising for high-speed actuation with high precision and bandwidth capability mainly due to the placement head being at the foundation of the motion chain, hence, a large mass of this device will result in high force/power requirements for the driving mechanism (i.e. an H-bridge with three linear permanent magnet motors placed in an H-configuration). This paper investigates a tubular actuator topology combined with passive gravity compensation. These two functionalities are separately introduced, where the combination is verified using comprehensive three dimensional (3D) finite element analyses.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.12
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• pp.691-700
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• 1999

This paper proposes a novel switching strategy of 1Mvar STATCON using cascade multilevel H-bridge inverter(HBI) for FACTS application. To control the reactive power instantaneously, the d-q dynamic system model is described and analyzed. A single pulse pattern based on the SHEM(Selective Harmonic Elimination Method) technique is determined from the look-up table to reduce the line current harmonics and a rotating fundamental frequency switching scheme is presented to adjust the DC voltage of each inverter capacitor at the same value. So the voltage unbalance problem between separately DC bus voltage is improved by using the proposed switching scheme. As a result, the presented inverter configuration not only reduces the system complexity by eliminating the isolation at the AC input side transformer but also improves the dynamic response to the step change of reactive power.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.87-90
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• 2009

Wireless Mesh Network(WMN) is wireless backbone networks technique which has ease of network configuration and cost of advantage. Recently, WNM released a new product, but most of existing research and technology analysis the performance through the simulation. This paper build the wireless mesh network testbed for actual situation. Testbed supports multi-channel multi-interface using bridge, the Wireless Distribution System and dynamic location-based routing protocol. This routing protocol strongly design against wireless interference using metric for link channel change and real distance. Then, the address of mesh clients assigned by the centralized address management server. Mesh clients is designed and implemented to manage network through Simple Network Management Protocol.

• Computers and Concrete
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• v.23 no.1
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• pp.69-80
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• 2019

Modeling approach for mesoscopic model of concrete depicting mass transportation and physicochemical reaction is important since there is growing demand for accuracy and computational efficiency of numerical simulation. Mesoscopic numerical simulation considering binder, aggregate and Interfacial Transition Zone (ITZ) generally produces huge number of DOFs, which is inapplicable for full structure. In this paper, a three-dimensional multiscale approach describing three-phase structure of concrete was discussed numerically. An effective approach generating random aggregate in polygon based on checking centroid distance was introduced. Moreover, ITZ elements were built by parallel expanding the surface of aggregates on inner side. By combining mesoscopic model including full-graded aggregate and macroscopic model, cases related to diffusivity and thickness of ITZ, volume fraction and grade of aggregate were studied regarding the consideration of multiscale compensation. Results clearly showed that larger analysis model in multiscale model expanded the diffusion space of chloride ion and decreased chloride content in front of rebar. Finally, this paper addressed some worth-noting conclusions about the chloride distribution and rebar corrosion regarding the configuration of, rebar diameter, concrete cover and exposure period.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.10
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• pp.55-61
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• 2018

Changes in consumer purchasing patterns due to construction of large Western-style commercial buildings and introduction of new purchasing methods in South Korea in the 1990s led to a gradual decline in traditional markets. Under such a new environment, Yukgeori market, one of Korea's exemplary markets, has continued to develop and survive, while maintaining the traditional market form of Korea, both physically and operationally. Therefore, to find the characteristics of spatial configurations supporting the revitalization of traditional market, we deduced social attributes of spaces in street network of Cheongju city and the neighborhood including Yukgeori market by calculating the depths of nodes in the network using analysis models based on space syntax. The results illustrated that long street with the function to attract people and acts as a bridge of traffic and communication between highly modernized commercial area and traditional market can lead to continuous win-win development of both areas and the revitalization of traditional market through the promotion of social activities in the market. We expect that sound and sustainable development of contemporary cities, which lost tradition, will be achieved through the results of this study.

• Steel and Composite Structures
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• v.48 no.4
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• pp.475-483
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• 2023

In this paper, a new energy-efficient semi-active hybrid bulk damper is developed that is cost-effective for use in structural applications. In this work, the possibility of active and semi-active component configurations combined with suitable control algorithms, especially vibration control methods, is explored. The equations of motion for a container bridge equipped with an MDOF Mass Tuned Damper (M-TMD) system are established, and the combination of excitation, adhesion, and control effects are performed by a proprietary package and commercial custom submodel software. Systematic methods for the synthesis of structural components and active systems have been used in many applications because of the main interest in designing efficient devices and high-performance structural systems. A rational strategy can be established by properly controlling the master injection frequency parameter. Simulation results show that the multiscale model approach is achieved and meets accuracy with high computational efficiency. The M-TMD system can significantly improve the overall response of constrained structures by modestly reducing the critical stress amplitude of the frame. This design can be believed to build affordable, safe, environmentally friendly, resilient, sustainable infrastructure and transportation.

• Steel and Composite Structures
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• v.50 no.2
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• pp.217-235
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• 2024

Concrete-filled steel tubes (CFSTs) nowadays are widely used as the main parts of momentous structures, and its connection has gained increasing attention as the complexity in configuration and load transfer mechanism. This paper proposes a novel CFST pier-to-footing incorporating tube-confined RC encasement. Such an innovative approach offers several benefits, including expedited on-site assembly, effective confinement, and collision resistance and corrosion resistance. The seismic behavior of such CFST pier-to-footing connection was studied by testing eight specimens under quasi-static cyclic lateral load. In the experimental research, the influences on the seismic behavior and the order of plastic hinge formation were discussed in detail by changing the footing height, axial compression ratio, number and length of anchored bars, and type of confining tube. All the specimens showed sufficient ductility and energy dissipation, without significant strength degradation. There is no obvious failure in the confined footing, while local buckling can be found in the critical section of the pier. It suggests that the footing provides satisfactory strength protection for the connection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1446-1455
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• 2016

The recent increase of fresh farm products, hazardous cargos, and high-priced goods in marine transportation has caused an increased demand of cargo owners and shipping companies with regard to the monitoring of the location and state of cargo. To meet this increase, numerous technologies are being studied for the monitoring of the cargo state. Cargo containers on a ship are loaded on a ship's deck and in a ship's hold, which is located under the deck. However, Since the developed technologies mostly transfer the container status information that collected by mobile communication, it costs a lot to install communication infrastructure on ship. And the ship's hold is completely sealed with a cover, and communication with the reader positioned at the ship's bridge is difficult. Therefore, most existing studies on container monitoring on ships have focused on the monitoring of containers loaded on a ship's deck. Accordingly, this study suggested system configuration for the monitoring of containers in a ship's hold using IP-RFID technology. The suggested system configuration was tested on an actual ship under navigation, and the test results are given in this study. The test results verified that the monitoring of containers in a ship's hold using IP-RFID technology is effective.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.825-829
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• 2015

Theoretical calculations suggest that the thermoelectric figure of merit (ZT) can be improved by introducing a core-shell heterostructure to a semiconductor nanowire because of the reduced thermal conductivity of the nanowire. To experimentally verify the decrease in thermal conductivity in core-shell nanowires, the thermal conductivity of Ge-SixGe1-x core-shell nanowires grown by chemical vapor deposition (CVD) was measured using suspended microdevices. The silicon composition (Xsi) in the shells was measured to be about 0.65, and the remainder of the germanium in the shells was shown to play a role in decreasing defects originating from the lattice mismatch between the cores and shells. In addition to the standard four-point current- voltage (I-V) measurement, the measurement configuration based on the Wheatstone bridge was attempted to enhance the measurement sensitivity. The measured thermal conductivity values are in the range of 9-13 W/mK at room temperature and are lower by approximately 30 than that of a germanium nanowire with a comparable diameter.

• Broadcasting and Media Magazine
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• v.10 no.1
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• pp.99-112
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• 2005

Christian Metz, the precursor of cine-semiology, considered cinema as a language in the sense that it is a set of messages grounded in a given matter of expression, and a signifying practice characterized by specific codifications. According to Metz, film forms a structured network produced by the interweaving of cinematic codes, within which cinematic subcodes represent specific usages of the particular code. For Metz, cinematic language is a totality of cinematic codes and subcodes, and history of the cinema is the trace of the competition, incorporations and exclusions of the subcodes. He also suggested a filmic text is not just a list of codes in effect, but a process of constant displacement and deformation of codes. Following Metz' textual analysis methodology, I investigated the formal configuration of Hayao Miyazaki‘s animation, Spirited Away. It is interesting to trace the interweaving of cinematic codes in Spirited Away, i.e. codes of lighting, color, movement, and auteurism, across the animation. I focused on the first scene at the bridge to Yubaba's bathhouse, analyzing each cinematic code and its subcode applied. The first bridge scene is carefully constructed to stand out the confrontation of Chihiro (with Haku) and the bathhouse. The bathhouse is not just a building, it represents the powerful witch, Yubaba, yet to appear on the scene, and functions as an antipode to Chihiro. In each shot, every subcode within the codes of framing, direction, angle, color, lighting and movement is used to maximize the contrast between the dominant bathhouse and the feeble 10-year-old girl. In Spirited Away, the subcodes within each cinematic ode are constantly competing and displacing each other to augment the antithesis between the characters and develop the narrative. As Metz's argument that film constitutes a quasi-linguistic practice as a pluricodic medium, Spirited Away communicates with the spectators with the combination and displacement of these cinematic codes and subcodes.