• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.9
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• pp.669-678
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• 2007

In this study, the ventilation characteristics is investigated numerically of the longitudinal ventilation method in the curved long road tunnel. Numerical work has been conducted for the jet fan location by utilizing the commercial finite-volume code, FLUENT. Configuration of the tunnel is three-lane, 1600 m long, $120m^2$ in area, 3000 m curvature radius. The velocity profile, distribution of mono-dioxide carbon and flow rate of air are examined in the tunnel. Through the analysis, it is found that the difference of ventilation flow rate Is a little by the jet fan location, but tunnel outlet setup (CASEIII) of jet fans is the most efficient concerned with CO concentration.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.77-86
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• 2008

Traditional cluster-based routing method is a representative method for increasing the energy efficiencies. In these cluster-based routing methods, the selected cluster head collect/aggregate the information and send the aggregated information to the base station. But they have to solve the unnecessary energy dissipation of frequent information exchange between the cluster head and whole member nodes in cluster. In this paper, we minimize the frequency of the information exchange for reducing the unnecessary transmit/receive frequencies as calculate the overlapped area or number of overlapped member nodes between the selected cluster head and previous cluster head in the setup phase. And besides, we consider the direction of super cluster head for optimal cluster formation. So, we propose the modified cluster selection scheme that optimizes the energy dissipation in the setup phase and reuses the saved energy in the steady phase efficiently that prolongs the whole wireless sensor network lifetime by uniformly selecting the cluster head.

• Journal of Korea Multimedia Society
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• v.11 no.8
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• pp.1082-1092
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• 2008

In wireless sensor networks, clustering protocol such as LEACH is an efficient method to increase whole networks lifetime. However, this protocol result in high energy consumption at the cluster head node. Hence, this protocol must changes the cluster formation and cluster head node in each round to prolong the network lifetime. But this method also causes a high amount of energy consumption during the set-up process of cluster formation. In order to improve energy efficiency, in this paper, we propose a new cluster formation algorithm. In this algorithm, we define a intra cluster as the sensor nodes within close proximity of each other. In a intra cluster, a node senses and transmits data at a time on the round-robin basis. In a view of whole network, intra cluster is treated as one node. During the setup phase of a round, intra clusters are formed first and then they are re-clustered(network cluster) by choosing cluster-heads(intra clusters). In the intra cluster with a cluster-head, every member node plays the role of cluster-head on the round-robin basis. Hence, we can lengthen periodic round by a factor of intra cluster size. Also, in the steady-state phase, a node in each intra cluster senses and transmits data to its cluster-head of network cluster on the round-robin basis. As a result of analysis and comparison, our scheme reduces energy consumption of nodes, and improve the efficiency of communications in sensor networks compared with current clustering methods.

• Korean Institute of Interior Design Journal
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• v.26 no.3
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• pp.101-112
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• 2017

Based on an analysis of the characteristics of "Ecute" of the East Japan Railway Company (JR East) that planned the world's first large scale commercial facilities inside a ticket gate (paid-area including waiting room and platforms), the present study proposes a brand development of commercial facilities inside aged railway stations, where only basic railway business have been provided focusing on passenger transportation, by renewing the definition of railway commercial facilities and presenting a detailed planning and the direction of the operation system. A list of practical tasks that can be carried out in academia, planning and operation / management to facilitate the revitalization of the use of commercial facilities inside railway stations are as follows: 1) the setting of a wide scope for the revitalization of railway commercial facilities around the railway station focusing on private-funded stations in addition to existing stations; a setup of the direct scope of commercial development in the practical railway operation for passengers and stations in terms of external research, and a corresponding shift in thinking in terms of internal research 2) development of under used spaces such as the transfer area (Gongdeok Seoul Wangsimri Station are first target stations where more than four subway lines intersect) 3) brand establishment through improvement strategies for image and symbolism specialized for railway stations 4) rent of suitable business stores and layout of commercial facilities by analysis of passenger move pattern 5) development of commercial facilities which can attract customers by displaying various products, as well as finding a way to develop them in to a base facility that connects to local infrastructures 6) providing advertisement and management system for continual maintenance, and 7) brand specialization through unique storytelling and design plan that stimulates sensibility. The above study results can be utilized as a starting point for design brand awareness about commercial facilities in railway stations in Korea, which can be developed further to improve station image and passenger convenience, as well as to increase the revenue of railway businesses.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.273-280
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• 2017

As massive integration technology of transistors has been developing, multi-core circuit is fabricated on a silicon chip and a clock frequency is getting faster to meet the system requirement. But increasing the clock frequency can induce some problems to violate the operation of system such as clock synchronization, so it is very import to avoid metastability events to design digital chips. In this paper, metastability windows are measured by bisection method in H-spice depending on temperature, supply voltage, and the size of transmission gate with D-FF designed with 180nm CMOS process. The simulation results show that the metastability window(: MW) is slightly increasing to temperature and supply voltage, but is quadratic to the area of a transmission gate, and the best area ration of P and Ntransitor in transmission gate is P/N=4/2 to get the least MW.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.24-35
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• 2016

By estimating environment light distribution, we can generate realistic shadow images in AR(augmented reality). When we estimate light distribution without sensing equipment, environment light model, geometry of virtual object, and surface reflection property are needed. Previous study using 3D marker builds surrounding light environment with a geodesic dome model and analyzes shadow images. Because this method employs candidate shadow maps in initial scene setup, however, it is difficult to estimate precise light information. This paper presents a novel light estimation method based on hierarchical light distribution model subdivision. By using an overlapping area ratio of the segmented shadow and candidate shadow map, we can make hierarchical subdivision of light geodesic dome.

• Journal of Energy Engineering
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• v.18 no.4
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• pp.239-246
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• 2009

A fundamental investigation has been conducted on the combustion of single particle of a sub-bituminous coal char burning at different temperatures and residence times. The lab-scale test setup consisted of a drop tube furnace where gas temperatures varied from $900^{\circ}C$ to $1400^{\circ}C$. A calibrated two color pyrometer, mounted on the top of the furnace, provided temperature profiles of luminous particle during a char oxidation. An amount of char mass reacted during the reaction is measured with thermogravimetry analyzer by using an ash tracer method. As a result, mass and area reactivity as well as reaction rate coefficients are determined for the char burning at atmospheric pressure condition.

• Polymer(Korea)
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• v.37 no.1
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• pp.1-4
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• 2013

We proposed a new process to fabricate a high-aspect-ratio microhair having surface wrinkles using the contact-and-tension of a microstamp. Through this work, we observed that regular surface wrinkles were generated on the hair with a diameter of around $20{\mu}m$ due to the uni-directional compressive stress during the photocuring process by ultraviolet light. To do this, we conducted an experimental system setup for contact-and-tension process. From the preliminary test results, we believed that the proposed method can be applied to make a long polymer hair having surface wrinkles for special applications to biomimetics, and some research fields related on surface area such as heat transfer and catalyst enhancement.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.117-132
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• 2020

The study studied ways to improve the adjustment of the cadastral reform project after analyzing and evaluating the method of determining the boundaries and the overall status of the adjustment, focusing on cases of complaints in the business district in Sejong City, where the re-investigation project was completed. Measures to improve the adjustment amount of the cadastral reform project were largely divided into boundary adjustment and improvement measures according to the scope of area allowance and institutional improvement. According to an analysis of the status of boundary adjustment in Sejong City, the boundary of the cadastral reform project was being adjusted in various ways, and among them, it was found that it is simple to adjust, to formalize parcels, and that many adjustments are being made centering on resolving blind areas by establishing new roads. When setting such a boundary, it is necessary to establish an efficient and reasonable boundary by actively encouraging sufficient consultation with owners and an adjustment boundary that reflects the personal will of landowners to minimize disputes over the adjustment amount. In terms of improvement measures based on the area limit, it is necessary to accurately record and preserve the results of the cadastral resurvey in numerical data and to ease or exempt the adjustment amount if it is within the area permissible scope of the Spatial Data Management Act when calculating the adjustment amount. Finally, in relation to the adjustment, it was judged that it would be necessary to provide long-term low-interest loans to their own land to landowners, and that it would be necessary to calculate the adjustment through appraisal calculated by third parties fairly and objectively based on value judgment.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.511-519
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• 2017

This Paper introduces the design and communication method between PLC (Programmable Logic Controller) and Arduino based on MODBUS Protocol. MODBUS connection can be established in a new or existing system very easily, therefore we used this protocol in our proposed system. In the field of automatic devices, multi-function serial port such as RS232, RS422, RS485, and so on creates a great convenience to the developer. This proposed system used RS485 as a key mediator for data exchanging on a connected network. We also believe that it will reduce the development cost in various automated industry because this system can be reused or can be implemented any such PLC installed machines. RS485 is used as a communication interface between PLC (as a slave) and Arduino (as a master), through which a reliable network is created for safe and fast communication. Furthermore, RS485 allows multiple devices(up to 32) to communicate at half duplex on a single pair of wires and provides a long connectivity area (up to 1200 meters) as compare to other device, which makes it a user-friendly for various devices in the automated industry. Moreover, Arduino can play as a mediator by connecting third party device and setup a communication network with PLC.