• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.187-201
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• 2016

The purpose of this study was to analyze the smart phone usage experience structure for college students. The phenomenology approach was used by conducting 4 times in-depth interviews with the 7 college students age between 20~23. Collected Data was analyzed by Giorgi's phenomenological method. There were 4 general structure descriptions and 28 themes. General structure descriptions were 'Dependence on smart phone', 'Phenomenon of smart phone usage', 'Results of smart phone usage' and 'Relationship between stress and smart phone'. Themes consisted of 'Ambivalence', 'Positive feelings for smart phones', 'Separation anxiety', 'Negative feelings for smart phones'. 'Dependent feelings for smart phones', 'A sense of unity with smart phones', 'Helpful for my life', 'Deeply involved with my life', 'Useful tool in my life', 'Study, communication, relaxation and health care', 'Maintain personal relationship', 'The most important thing in my life', 'Shallow relationship stress', 'Interference with personal relationship', 'Forming a negative relationship', 'Invasion of privacy', 'Forming a Incorrect relationship', 'Unwanted participation', 'No effort to improve relationship', 'Poor concentration', 'Interference with academic study', 'Study assistance', 'Limited help for study in depth', 'Shelter from the stress', 'Amplification of the stress', 'Obsessive focus', 'Feel separation for the reality' and 'Waste of time'. Smart phone usage make college students dependent on smart phones and had negative influence on both personal relationship and academic results. Usage of smart phone also amplified stress. Therefore we need fundamental principles on usage of smart phone and propose to build cultural etiquette that provides reasonable way to use smartphone.

• Journal of Astronomy and Space Sciences
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• v.19 no.4
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• pp.273-282
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• 2002

We describe some performance of the detector electronics system for the FIMS (Far-ultraviolet Imaging Spectrograph) mission. The FIMS mission to map the far ultraviolet sky uses MCP (micro-channel plate) detectors with a crossed delay line anode to record photon arrival events. FIMS has two MCP detectors, each with a ~25mm$\times$25mm active area. The unconventional anode design allows for the use of a single set of position encoding electronics for both detector fields. The centroid position of the charge cloud, generated by the photon-stimulated MCP, is determined by measuring the arrival times at both ends of the anode following amplification and external delay. The temporal response of the detector electronics system determines the readout's positional resolution for the charge centroid. High temporal resolution (<$35{\times}75$ps FWHM) and low power consumption (< 6W) were achieved for the FIMS detector electronics system.

• Journal of Korean Society of Forest Science
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• v.105 no.3
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• pp.309-314
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• 2016

A locally adapted plant population under harsh environmental changes might survive for a long generation through maintaining proper level of genetic diversity. When it happens losing the genetic diversity too much fast, the population could be declining and probably become extinct. An isolated small population of Populus davidiana was investigated to study out the genetic diversity and the fine-scale spatial genetic structure. The estimated number of adult trees in the population of Mt. Worak, South Korea, was 350 in the total area of $14,000m^2$. The number of adults in a study plot ($70m{\times}70m$) was 123. The average age was 16-year-old and a 32-year-old tree was the oldest. The distribution of individuals was slightly aggregated in the plot. Sixty-one among the 123 individuals were randomly sampled to estimate genetic variation using AFLP markers. One hundred fifty-one (77%) of total 196 amplicons were polymorphic from six AFLP primer combinations. The average number of loci per primer combination was 32.7 (S.D.=7.2). Expected heterozygosity ($H_e$) and Shannon's diversity index (S.I.) were 0.154 and 0.254, respectively. These values were extremely lower than those of other P. davidiana populations in South Korea. Genetic patchiness was showed within 21 meters by spatial autocorrelation analysis and the isolated small size of population might be mainly attributed to the formation of such small patch size.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.337-346
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• 2020

Traffic jam and congestion in urban areas has caused the need to improve the utility of underground space. In response, research on underground structures is increasingly being conducted. Notably, a double-deck tunnel is one of the most widely used of all those underground structures. This double-deck tunnel is separated by the middle slab into the upper and lower roadways. Both vehicle load and earthquake load cause the middle slab to exhibit dynamic behavior. Earthquake-related response characteristics, in particular, are highly complex and difficult to interpret in a theoretical context, and thus experimental research is required. The aim of the present study is to assess the stability of a double-deck tunnel's middle slab of the Collapse Prevention Level and Seismic Category 1 with regard to the presence of vibration-damping Rubber Bearings. In vibration table tests, the ratio of similitude was set to 1/4. Linings and vibrating platforms were fixed during scaled model tests to represent the integrated behavior of the ground and the applied models. In doing so, it was possible to minimize relative behavior. The standard TBM cross-section for the virtual double-deck tunnel was selected as a test subject. The level of ground motion exerted on the bedrock was set to 0.154 g (artificial seismic wave, Collapse Prevention Level and Seismic Category 1). A seismic wave with the maximum acceleration of 0.154 g was applied to the vibration table input (bedrock) to analyze resultant amplification in the models. As a result, the seismic stability of the middle slab was evaluated and analyzed with respect to the presence of vibration-damping rubber bearings. It was confirmed that the presence of vibration-damping rubber bearings improved its earthquake acceleration damping performance by up to 40%.

• The KIPS Transactions:PartA
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• v.11A no.3
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• pp.173-180
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• 2004

Quadtree, which 11 a hierarchical data structure, is a very important data structure to represent images. The linear quadtree representation as a way to store a quadtree is efficient to save space compared with other representations. Therefore, it has been widely studied to develop efficient algorithms to execute operations related to quadtrees. The region expansion is an operation to expand images by a given distance and the scaling If an operation to scale images by a given scale factor. In this paper, we present algorithms to perform the region expansion and scaling of images represented by quadtrees, using three-dimensional n${\times}$n${\times}$n processors on RMESH(Reconfigurable MESH). These algorithms have constant time complexities by using efficient basic operations to route the locational codes of quadtree on the hierarchical structure of n${\times}$n${\times}$n RMESH.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1061-1068
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• 2019

Cooperative networks transmit signals form the source node to the destination node via several relay node where the combining and demodulation of relay aided signals provide the benefit of performance enhancement and data rate increment. In general, a repetitive manner transmission scheme in which the received signal from the source node is amplified/re-generated and forward to the destination node is widely used. In this paper, we analyzed the performance of cooperative networks using the mixed transmission scheme. The conventional modulation scheme is used in the source-relay links, and space-time code is applied in the relay-destination links. To reduce the complexity of the overall system, we adopt differential modulation which bypasses channel state information. We analyze bit error rate (BER) of the proposed system by considering the number of relay nodes, and the performances depending on the strength of transmission signal in the source-relays and rely-destination links are compared. In addition, we also discuss the system performance with the signal strength and the number of relay nodes simultaneously.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5452-5459
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• 2014

A resonance linear electric generator in a vehicle suspension is a system that performs self-electric generation by collecting the vibration energy when a vehicle runs on a road, and takes the resonance phenomenon to derive large electric generation from slight road surface vibrations. In this paper, the motions of an armature in three different electric generator structures were simulated and the actual generation quantity was calculated and compared with these results. Furthermore, when the vehicle runs on the road, the design improvement for a multi-degree of freedom electric generator was conducted to make the resonance respond to various excitation frequencies, and the change in the resonance points and generation quantity were identified.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.88-101
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• 2011

Locative media is fundamentally different from traditional media in terms of being packed with user's space, place, and position nearby, which does not simply mean user's physical coordinates. This study has been started that I was drawn by the tendency of which current locative media contents are based on 'location-based information,' and closely related with 'Augmented Reality.' I wonder how media user's psychological experience/involvement are revealed when the media environment changes by the progress of technology. I wonder how media users perceive 'social presence' formed by locative media in current locative media environment. Particularly, the fact that user's perception of social presence formed in locative media conflicts with the previous computer-mediated communication(CMC)'s attributes deepened my curiosity. In this study, the idea of 'more-proper-construct' is suggested, the characteristics of social presence in current locative media is considered, and is investigated by qualitative methodology how the 'location-based' attributes and 'AR' contribute to forming the social presence.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.175-176
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• 2013

Currently barbola has been considered in Korea. The artistry of it has been studied. Interior design barbola has developed from an art activity to a real life product. Interior design is meant to total design activity to satisfy all condition both function and emotion suited for the goal of interior space human dwells. We study the product technique of optic media barbola sculpture with affection and refinement to use traditional superior onion on optic media and permeability in order to apply the artistry of barbola to interior design. We make real sculpture using it. The mineral electric radiation sheet in this research includes 0.2mm thickness with low power, high brightness, and non-heat. The result of this study contains a new type and narrative beyond the limitation of the traditional barbola. We make power saving lighting sculpture through it.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.197-200
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• 2003

In order to establish effective in situ PCR on the glass slide using the conventional DNA thermal cycler, several parameters should be considered. These include full accessibility of PCR reagents into the cells, prevention of diffusing PCR products out of the cells, loss of PCR reagents by nonspecific adherence onto the glass slide, dryness of PCR reagents by heat, and heat conductivity from the heat block to the glass slide. Especially, to guarantee the full accessibility of PCR reagents to sample, relatively higher concentration of PCR reagents (particularly 4.5 mM of $Mg^{++}$) was required while 5 to 10 units/50 ${\mu}l$ reaction of Taq enzyme was enough as long as the step of pre-PCR incubation was included. Dryness of sample was prevented by addition of distilled water into the empty slots in the heat block, thereby providing the reproducible temperature-time profile of PCR. Observed temperature was lower than the programmed temperature by 3 to $4^{\circ}C$.