• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.393-396
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• 2009

This paper describes a design of variable-length FFT/IFFT processor for OFDM-based communication systems. The designed FFT/IFFT processor adopts the in-place single-memory architecture, and uses a hybrid structure of radix-4 and radix-2 DIF algorithms to accommodate FFT lengths of $N=64{\times}2^k$ ($0{\leq}k{\leq}7$). To achieve both memory size reduction and the improved SQNR, a two-step conditional scaling technique is devised, which conditionally scales the intermediate results of each computational stage. The performance analysis results show that the average SQNR's of 64~8,192-point FFT's are over 60-dB. The processor synthesized with a $0.35-{\mu}m$ CMOS cell library can operate with 75-MHz@3.3-V clock, and 64-point and 8,192-point FFT's can be computed in $2.55-{\mu}s$ and $762.7-{\mu}s$, respectively, thus it satisfies the specifications of wireless LAN, DMB, and DVB systems.

• Journal of the Korean Geographical Society
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• v.48 no.4
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• pp.589-607
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• 2013

Writing to heal is a writing that the self chews over his/her life and expresses what he/she is. Recently, many scholars who concern with writing to heal show interests in place as a medium to heal. From this point of time, this study aims to interpret implications of the writing to heal mediated by places as catalyst on the bases of theories that have argued the reciprocity between memory[the self] and place. Previously, the author has drawn 'The places that have shaped his/her life', the theme to write, and secondly interpret various situations and aspects of writings that students put down. As a result, the author places emphasis on that most students have a variety of memorial places respectively and those places work as catalyst in the process of writing.

• Korean Institute of Interior Design Journal
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• v.21 no.1
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• pp.186-194
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• 2012

One hand shopping center provides a public space for people, the other hand it is a place for commercial purpose. Although it gives an entertainment, eating and shopping places to people nowaday, owners and tenants aim to make profit from it. According to this demand designers should plan a shopping center for a comfortable place for eating, shopping and playing and they make shops and retails to increase sales by exposing those to more people at the same time. For successful shopping center architects are requested an approach with commercial strategy that shopping center raises exposure of retails and makes stay costumers longer and visit more frequently. Recently space is regarded as a mean of marketing, so-called "place marketing", because it can influence on brand image and improves the image of product. Therefore, it need to be approached with commercial consideration. Analyzing the armature this study will take a look at spatial strategies in shopping centers which especially the Jerde Partnership, one of influential firms on commercial space, designed. And it will examine how spatial strategies can be applied to commercial strategies in relation to customer information process(exposure-attention-interest-comprehension-memory) which marketers are using in advertisement for marketing and what kind of role spatial strategies can be. This study is to be basic considerations when a shopping center project will be planned.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.651-660
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• 2008

Flash memory is widely used in embedded systems because of its benefits such as non-volatile, shock resistant, and low power consumption. However, NAND flash memory suffers from out-place-update, limited erase cycles, and page based read/write operations. To solve these problems, YAFFS and RFFS, the flash memory file systems, are proposed. However YAFFS takes long time to mount the file system, because all the files are scattered all around flash memory. Thus YAFFS needs to fully scan the flash memory. To provide fast mounting, RFFS has been proposed. It stores all the block information, the addresses of block information and meta data to use them at mounting time. However additional operations for the meta data management are decreasing the performance of the system. This paper presents a new NAND flash file system called ERFFS (Efficient and Reliable Flash File System) which provides fast mounting and recovery with minimum mata data management. Based on the experimental results, ERFFS reduces the flash mount/recovery time and the file system overhead.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.981-984
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• 2005

This study is to realize its threshold voltage shift after programming operation in charge trap type SONOS memory by simulation. SONOS devices are charge trap type nonvolatile memory devices in which charge storage takes place in traps in the nitride-blocking oxide interface and the nitride layer. For simulation of their threshold voltage as a function of the memory states, traps in the nitride layer have to be defined. However, trap models in the nitride layer are not developed in commercial simulator. So, we propose a new method that can simulate their threshold voltage shift by an amount of charges induced to the electrodes as a function of a programming voltages and times as define two electrodes in the tunnel oxide-nitride interface and the nitride-blocking oxide interface of SONOS structures.

• The Korean Journal of Archival Studies
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• no.60
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• pp.123-159
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• 2019

Given that the concept of reproducing landscape is similar to that of recording historical sights, places can become special space where memories are archived through meaningful activities. Therefore, place and landscape are the important concepts for understanding the Home of Roh Moo-hyun. This research was initiated when Roh Moo-hyun Foundation's decided to return the Home of Roh Moo-hyun to the public. A research report was published as the first result of this initiative. Then an archive book was recently published based on the first research report. The research report was about philosophical and aesthetic meanings and contents, the layers of accumulated memories, the records based on the accumulated memories, and the attributes of the place, and the possibility of archiving, whereas the purpose of the archive book is to restore and to curate the original meaning of the Home of Roh Moo hyun through cultural events. There are 'three memories' of layers in the Home of Roh Moo-hyun. The first memory is about 'life and dreams' that President Roh Moo-hyun dreamed about after his retirement to the hometown. The second memory is about 'the loss of time' for 10 years of time after the decrease of the President Roh Moo-hyun. The third memory is 'the memory of citizens', which started with the public opening of the Home of Roh Moo-hyun. 'Low Roof House of President Roh Moo-hyun' is the archive book that comprises the three memories which are accumulated in the home of Roh Moo-hyun and 'record language' full of meanings.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1098-1100
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• 2005

The floorplanning problem is an essential design step in VLSI layout design and it is how to place rectangular modules as density as possible. And then, as the DSM advances, the VLSI chip becomes more congested even though more metal layers are used for routing. Usually, a VLSI chip includes several buses. As design increases in complexity, bus routing becomes a heavy task. To ease bus routing and avoid unnecessary iterations in physical design, we need to consider bus planning in early floorplanning stage. In this paper, we propose a floorplanning method for topological constraint consisting of bus constraint and memory constraint. The proposed algorithms based on Genetic Algorithm(GA) is adopted a sequence pair. For selection control, new objective functions are introduced for topological constraint. Studies on floor planning and cell placement have been reported as being applications of GA to the LSI layout problem. However, no studies have ever seen the effect of applying GA in consideration of topological constraint. Experimental results show improvement of bus and memory constraint.

• ETRI Journal
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• v.28 no.6
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• pp.697-708
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• 2006

Various adaptive mesh refinement techniques are often employed in numerical simulations for increasing spatial and temporal resolution beyond the limits imposed by available CPU time and memory space. Recently, an octree-based adaptive mesh structure was successfully used in fluid animation to place more grid cells efficiently in visually interesting regions of fluids. In an attempt to optimize the use of computational resources further in fluid animation, this paper extends this adaptive technique by modifying the mesh refinement scheme so that the camera's viewing properties are dynamically exploited during the simulation. Based on a simple adaptive mesh structure, we show that the new meshing strategy can save a substantial amount of computation time and memory space by using a view-dependent adaptive approach. The experimental results reveal that the proposed technique provides a good compromise between the computational effort and the simulation's fidelity, and may be used quite effectively in 3D animation production.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.278-283
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• 2015

In this work, the electrical bistability of an organic CT complex is demonstrated and the possible switching mechanism is proposed. 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and tetracyanoquinodimethane (TCNQ) are used as an organic donor and acceptor, respectively, and poly-methamethylacrylate (PMMA) is used as a polymeric matrix for spin-coating. A device with the Al/($Al_2O_3$)/PMMA:BCP:TCNQ[1:1:0.5 wt%]/Al configuration demonstrated bistable and switching characteristics similar to Ovshinsky switching with a low threshold voltage and a high ON/OFF ratio. An analysis of the current-voltage curves of the device suggested that electrical switching took place due to the charge transfer mechanism.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.657-657
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• 2013

In-situ observations of nano-scale behavior of nanomaterials are very important to understand onthe nano-scale phenomena associated with phase change, atomic movement, electrical or optical properties, and even reactions which take place in gas or liquid phases. We have developed on the in-situ experimental technologies of nano-materials (nano-cluster, nanowire, carbon nanotube, and graphene, et al.) and their interactions (percolation of metal nanoclusters, inter-diffusion, metal contacts and phase changes in nanowire devices, formation of solid nano-pores, melting behavior of isolated nano-metal in a nano-cup, et al.) by nano-discovery membrane platform [1-4]. Between two microelectrodes on a silicon nitride membrane platform, electrical percolations of metal nano-clusters are observed with nano-structures of deposited clusters. Their in-situ monitoring can make percolation devices of different conductance, nanoclusters based memory devices, and surface plasmonic enhancement devices, et al. As basic evidence on the phase change memory, phase change behaviors of nanowire devices are observed at a nano-scale.