• Title/Summary/Keyword: UNSTABILITY

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Factors affecting startup intention of retired office-workers (직장인들의 은퇴후 창업의도에 미치는 영향 요인)

  • Choi, Yang-Lim;Ha, Kyu-Soo
    • Journal of Digital Convergence
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    • v.10 no.9
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    • pp.195-212
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    • 2012
  • Most of the office-workers are worrying about their future and try to make diverse future plan. Fast shifting industry pattern make office-workers retire early and their remain life time are getting longer and many of them try to consider some kind of new start-up. In this article factors affecting entrepreneurial intention were discussed such as individual factors, psychological factors, environmental factors. Individual factors were economic situations and future life expectation were analyzed. Psychological factors were composed of risk taking tendency, self efficiency, career value, and entrepreneurial characteristics were discussed. Environmental factors were composed of recognition on social-economic risks and recognition on negative mind on start-up, and employment unstability. 340 sample questionaries were collected and 26 samples were excluded. Data were analyzed by SPSS Win 18.0 Version. The results of the study were as follows. Among individual factors life-expectation after retirement was positive impact on entrepreneurial intention. Among psychological factors risk taking factor has positive impact on entrepreneurial intention. Among Environmental factors negative recognition on start-up has negative impact on entrepreneurial intention. Based on the studies diverse understanding and implementation of policies were necessary to change negative social atmospheres on start-up.

The Performance Analysis of CCA Adaptive Equalization Algorithm for 16-QAM Signal (16-QAM 신호에 대한 CCA 적응 등화 알고리즘 성능 분석)

  • Lim, Seung-Gag
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.13 no.1
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    • pp.27-34
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    • 2013
  • This paper deals with the performance anlysis of CCA adaptive equalization algorithm, that is used for reduction of intersymbol interference at the receiving side which occurs in the time dispersive communication channel. Basically, this algorithm is borned for the solving phase unrecovery problem in the CMA equalizer, and the comines the concept of DDA (Decision Directed Algorithm) and RCA (Reduce Constellation Algorithm). The DDA has a stable convergence characteristics in unilevel signal, but not in the number of levels in multilevel signal such as QAM, so it has unstable problem. The RCA does not provide reliable initial convergence. And even after convergence, the equalization noise due to the steady state misadjustment exhibited by it is very high as compared to DDA. For the solving the abovemensioned point, the CCA adaptive eualization alogorithm has borned. In order to performance analysis of CCA algorithm, the recovered signal constellation that is the output of the equalizer, the convergence characteristic by the residual isi and MD (maximum distortion), the SER characteristic are used by computer simulation and it was compared with the DDA, RCA respectively. As a result of simulation, the DDA has superior performance than other algoithm, but it has a convergence unguarantee and unstability in the multilevel signal. In order to solving this problem, the CCA has more good performance than RCA in every performance index.

A Relief Method to Obtain the Solution of Optimal Problems (최적화문제를 해결하기 위한 완화(Relief)법)

  • Song, Jeong-Young;Lee, Kyu-Beom;Jang, Jigeul
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.1
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    • pp.155-161
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    • 2020
  • In general, optimization problems are difficult to solve simply. The reason is that the given problem is solved as soon as it is simple, but the more complex it is, the very large number of cases. This study is about the optimization of AI neural network. What we are dealing with here is the relief method for constructing AI network. The main topics deal with non-deterministic issues such as the stability and unstability of the overall network state, cost down and energy down. For this one, we discuss associative memory models, that is, a method in which local minimum memory information does not select fake information. The simulated annealing, this is a method of estimating the direction with the lowest possible value and combining it with the previous one to modify it to a lower value. And nonlinear planning problems, it is a method of checking and correcting the input / output by applying the appropriate gradient descent method to minimize the very large number of objective functions. This research suggests a useful approach to relief method as a theoretical approach to solving optimization problems. Therefore, this research will be a good proposal to apply efficiently when constructing a new AI neural network.

Switching Positionality of Border Region as Exceptional Space (예외 공간으로서 접경지역의 위치성 전환)

  • Kim, Boo-Heon;Lee, Sung-Cheol
    • Journal of the Economic Geographical Society of Korea
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    • v.20 no.3
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    • pp.267-286
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    • 2017
  • The main purpose of this paper is to identify the spatiality of North Korea and China border regions through investigating the exceptional characteristics of the regions with the concept of positionality, which allows us to realize the relative position between subject and object. Border regions could be identified appropriately by considering the concept of switching positionality, as it is a kind of multiple space in which its sudden closure and opening should be configured in accordance with geopolitical and geoeconomic changes centering around border line. The main arguments of this research concerned with border regions with the concept of switching positionality are fallen into three. Firstly, changes in border regions should be analyzed by investigating more broader contexts and conjunctural perspectives, and even an internal condition stemmed from locality. Secondly, trajectories of border regions could be analyzed by the assemblages of various powers. Finally, the positionality of economic actors should be examined by identifying dynamic relations between geoeconomics and geopolitics. In particular, the concept of positionality has led to a number of insights into discussions on time-space, and spatiality in relational-dialectical, socio-spatial, and power-topological perspectives. Based upon this concept of positionality, the research has identified exceptional characteristics in North Korea and China border regions. It argues that the exceptionality of the region has stemmed from the intersection between the unstability of geopolitical security and various geoeconomic benefits.

Hydraulic Resistance Characteristics of Compacted Weathered Granite Soil by Rotating Cylinder Test and Image Analysis (영상처리기법과 회전식 수리저항성능 실험을 이용한 다짐화강풍화토의 수리저항특성 분석)

  • Kim, Young Sang;Lim, Jae Seong
    • Journal of the Korean Geotechnical Society
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    • v.32 no.7
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    • pp.25-34
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    • 2016
  • Recently, in Korea, problems related with unstability of slope or sinkhole in urban area due to erosion of compacted granite soil which was used as a backfill or embankment material have been treated as important issues. Small hole might develop inside of backfill area due to erosion of not only weathered granite soil but also clay, silt, fine sand size particles when underground water flows. Once erosion starts in a soil mass, erosion rate increases gradually to cause rapid destruction. In this study, a rotating cylinder test (RCT) was performed to evaluate the hydraulic resistance characteristics of compacted weathered granite soil under various relative densities and preconsolidation pressures. Meanwhile, an image analysis method was introduced to analyze radius of irregularly eroded sample. It was found that image analysis is an effective means of minimizing the error in calculating a critical shear stress and threshold shear stress on the irregularly eroded sample. Furthermore, in general, hydraulic resistance capacity increases with the increase of relative density and preconsolidation pressure.

Structural Stability, Weathering and Conservation Method of Granite Standing Sculptured Buddha at Hwangsang-dong, Kumi (구미 황상동 마애여래입상의 구조적 안정성, 풍화 및 보존방안)

  • Lee, Chan Hee;Choi, Suck Won;Suh, Mancheol;Chae, Sang Jeong
    • Journal of Conservation Science
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    • v.9 no.1
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    • pp.21-32
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    • 2000
  • Rock composition of the Hwangsang-dong Granite Standing Sculptured Buddha (Treasure No. 1122) in the Kumi City is biotite-hornblende granodiorite which consists of about 30 pieces of individual rock blocks of same compositions. However, the cap rocks is pebble-bearing coarse sandstone. Rock blocks of the Standing Buddha and surrounding out crops occur well developed several joint systems of $N25^{\circ}$ to $45^{\circ}W$ strike and nearly vertical (70 to $85^{\circ}SE$) dipping. Rock blocks of the Standing Buddha showed vertical, horizontal and oblique joints, and those blocks are well supported by individual blocks. However, the junction part of the blocks are under dangerous situation due 10 seriously mechanical and chemical weathering. Host rock of the Standing Buddha belongs to the HW grade, therefore mostly rock-forming minerals of the granodiorite Standing Buddha altered with clay and iron hydroxide minerals by mineralogical and chemical weathering. Near surface of the Standing Buddha show spore and mycelium of green algaes, and a joint plane alive with weeds. We suggest that if structural stability for the Standing Buddha remove essentially a unstable rock blocks from the main body, and the main body necessitate supporting by rock bolting method because of repeated unstability and minimizing stress to the rock blocks. For the opened joint planes, fractured surface and alive weeds will attempt to fill in a petro-epoxy, petro-filler and biochemical treatments for the algaes, and ground water curtain and wall seems to be necessary for water flow and diminishing humidity of the Standing Buddha.

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HISTOLOGICAL AND CLINICAL STUDY OF ARTIFICIAL DERMIS IMPLANTATION FOR RESTORATION OF SOFT TISSUE DEFECTS (연조직 결손부 회복을 위한 인공진피 이식의 조직학적 및 임상적 연구)

  • Ryu, Sun-Youl;Kim, Sun-Kook
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.32 no.5
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    • pp.410-417
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    • 2006
  • The present study was aimed to compare the resorption rate and the histological change of the autogenous dermis and the artificial dermis (Terudermis$^{(R)}$) after the transplantation, and to report the clinical results of the use of Terudermis$^{(R)}$ in order to restore the soft tissue defect. Twenty mature rabbits, weighing about 2 kg, were used for the experimental study. The autogenous dermis and the Terudermis$^{(R)}$ size 1${\times}$1 cm were transplanted to the space between the external abdominal oblique muscle and the external abdominal oblique fascia of the each rabbits. They were divided into 4 groups (n=5 each) and gathered at 1, 2, 4, and 8 weeks after the transplantation. The resorption rate was calculated, and H-E stain was preformed to observe the histological changes. The chart review of the 17 patients who received Terudermis$^{(R)}$ graft to the facial soft tissue defects was conducted for the clinical study. The resorption rate at 8 weeks after the transplantation was 21.5% for the autogenous dermis, and 36.4% Terudermis$^{(R)}$. In microscopic examinations, the infiltration of the inflammatory cells and the epidermal inclusion cyst were observed in the autogenous dermis graft. The neovascularization and the progressive growth of the new fibroblast were shown in the Terudermis$^{(R)}$ graft. In clinical data of 17 patients, the size of the grafted Terudermis$^{(R)}$ was from 1.5$cm^2$ to 7.5$cm^2$ (average 3.5$cm^2$). Follow-up ranged from 5 to 25 months. Fourteen patients with cleft palate demonstrated stability of the graft and unremarkable complications. But unstability of the graft and the partial relapse were observed in three patients received the vestibuloplasty. These results indicate that Terudermis$^{(R)}$ can be available substitute of autogenous dermis because of the stability about resorption, the histocompatibility, and the unremarkable clinical complications.

The Demersal Fish of Asan Bay -IV. Temporal Variation in Species Composition from 1990 to 1993- (아산만 저어류 -IV 종조성의 최근 3년간(1990-1993) 변화-)

  • LEE Tae-Won;HWANG Sun-Wan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.28 no.1
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    • pp.67-79
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    • 1995
  • Temporal variation of demersal fish in Asan Bay was determined by analyzing seasonal samples collected by an otter tyawl from November 1990 to August 1993. Of 49 species identified, Cynogiossus joyneri, Thrissa koreans and Johnius belengerii predominated in abundance, consisting of $84.7\%$ in fish numbers and $70.5\%$ in biomass. The number of species did not show any significant seasonal variation. Fish numbers and biomass were comparatively high 3n spring, summer and tall, and low in winter. Community structure, analyzed by principal component analysis using rank correlation, showed a clear seasonal trend, which seems to be related to the seasonal effects such as temperature. The number of species and their abundance in the study area were lower than those in other embayments of Korean peninsula. It seems that unstability of the sediments by tidal mixing caused this phenomenon. The total number of species decreased annually. The species of which the frequency of occurrence tends to diminish as time were mainly composed of the species which rarely occurred with low abundance.

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Characteristics of Precipitation over the East Coast of Korea Based on the Special Observation during the Winter Season of 2012 (2012년 특별관측 자료를 이용한 동해안 겨울철 강수 특성 분석)

  • Jung, Sueng-Pil;Lim, Yun-Kyu;Kim, Ki-Hoon;Han, Sang-Ok;Kwon, Tae-Yong
    • Journal of the Korean earth science society
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    • v.35 no.1
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    • pp.41-53
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    • 2014
  • The special observation using Radiosonde was performed to investigate precipitation events over the east coast of Korea during the winter season from 5 January to 29 February 2012. This analysis focused on the various indices to describe the characteristics of the atmospheric instability. Equivalent Potential Temperature (EPT) from surface (1000 hPa) to middle level (near 750 hPa) was increased when the precipitation occurred and these levels (1000~750 hPa) had moisture enough to cause the instability of atmosphere. The temporal evolution of Convective Available Potential Energy (CAPE) appeared to be enhanced when the precipitation fell. Similar behavior was also observed for the temporal evolution of Storm Relative Helicity (SRH), indicating that it had a higher value during the precipitation events. To understand a detailed structure of atmospheric condition for the formation of precipitation, the surface remote sensing data and Automatic Weather System (AWS) data were analyzed. We calculated the Total Precipitable Water FLUX (TPWFLUX) using TPW and wind vector. TPWFLUX and precipitation amount showed a statistically significant relationship in the north easterly winds. The result suggested that understanding of the dynamical processes such as wind direction be important to comprehend precipitation phenomenon in the east coast of Korea.

Effects of Environmental Factors on the Stability and Vegetation Survival in Cutting Slope of Forest Roads (임도 절토 비탈면의 안정과 식생활착에 미치는 환경인자의 영향)

  • Jung, Won-Ok
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.4 no.2
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    • pp.74-83
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    • 2001
  • The purpose of this study was investigate to the influence of forest roads characteristics and environment factors on the soil erosion, stability and vegetation survival of cut slope in forest roads. The results obtained could be summarized as follows; 1. The correlated factors between slope erosion and variables in cut slope were altitude, convex, degree of slope, length of slope and soil depth. In the stepwise regression analysis, length of slope and soil hardness was a high significant and its regression equation was given by -89.6136 + 15.0667X14 + 16.6713X15($R^2$ = 0.6712). 2. The main factors influencing the stability of cut slope were significant in order of coverage, middle, convex, length of slope and north, and its discriminant equation was given by -1.019 + 0.064X22 - 0.808X8 - 0.622X24 + 0.742X11 - 0.172X14 - 0.545X6 ($R^2$ = 0.793). 3. The centroids value of discriminant function in the stability and unstability estimated to 1.244 and -1.348, respectively. The boundary value between two groups related to slope stability was -0.1038. The prediction rate of discriminant function for stability evaluation of was as high as 91.3%. 4. The dominant species of invasion vegetation on the cut slope consist with Carex humilis, Agropyron tsukushiense var. transiens, Calamagrostis arundinacea, Miscanthus sinensis var. purpurascens, and Ixeris dentata in survey area. The rate of vegetation invasion more increased by time passed. 5. The life form of invasion vegetation in cut slop showed to $H-D_1-R_{2,3}-e$ type of the hemicryptophyte of dormancy form, dissem inated widely by wind and water of dissminule type, moderate extent and narrowest extent of radicoid type, erect form of growth form. 6. The correlated factors between forest enviroment and coverage appeared north, passage years and middle position of slope at 5% level. The forest environment factors influencing the invasion plants in survey area were shown in order to altitude, passage years, rock(none), forest type(mixed) and stone amount. The regression equation was given by 17.5228 - 0.0911X3 + 3.6189X28 15.8493X22 19.8544X25 + 0.3558X26 ($R^2$ = 0.4026).

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