• Korean Journal of Cognitive Science
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• v.34 no.1
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• pp.39-66
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• 2023

New media moved the place of social exchange to the Internet, allowing large groups to communicate in one place beyond the limits of time and space. Recent studies have also reported cases in which human social abilities do not keep up with the expansion of group scale through social media. In this context, current study investigated how human perception of social information is affected by the expansion of the group scale in the context of majority bias. Using Internet-based task, the psychological processes that group ratio and group size are perceived and affect majority-biased social information use were investigated, and whether group scale moderates those processes was examined. The group ratio has a positive effect on the majority bias, and the relationship was partially mediated by ratio perception. Group scale did not moderate the relationship between group ratio and ratio perception. On the other hand, the correlation between group size and majority-biased social information use was not significant. Group scale moderates group size perception. The group size and size perception showed positive correlation under the smaller group scale condition. However under the extended group scale condition, the perceived group size became significantly lower and lost its correlation with group size. These results provide evidence that the psychological mechanism related to group size perception was not properly responding to the expansion of the group scale. Furthermore, the possibility of a specific psychological mechanism for processing group size information and the form of information input specifically accepted by majority bias were discussed from perspective of evolutionary psychology.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.497-501
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• 2005

근래 들어 도시화로 인한 물순환 파괴를 근본적으로 연구하고 이를 정상화하기 위한 체계적이고 통합적인 유역관리 기술이 요구되고 있다. 유역통합관리의 이론을 실제로 적용한 계획을 세우기 위해서는 Heathcote(1998)가 제안한 다음과 같은 단계별 절차를 수행하는 것이 바람직하다. 단계별 절차는 (1) 대상유역에 대한 정보수집, (2) 문제점 도출, (3) 분명한 목적 수립, (4) 대안의 구성, (5) 대안의 검토, (6) 대안의 효과분석, (7) 최종계획 수립으로 이루어져 있으며 본 연구에서는 3단계의 과정에 해당된다. Heathcote(1998)는 대안의 선정과 평가를 위한 방법으로 단순평가방법(simple assessment method)과 세부평가방법(detailed assessment method)으로 구분하였는데 본 연구에서 수행한 내용은 단순평가방법에 해당된다. 본 연구는 안양천 유역에서 물순환 건전화의 핵심을 건천화 방지로 판단하고 이를 위한 대안을 크게 지표수, 지하수, 대체수자원 분야로 구분하여 제시하였다. 지표수 분야의 경우 구조적인 대안으로 소규모 저수지의 개발, 타유역에서의 도수, 보를 이용한 수량 확보, 우오수분리벽을 이용한 상류유출수의 확보, 저협수로 형성, 하천바닥에 차집관로 매설 방지 및 차집관로 유지관리 등이 있으며 비구조적인 대안으로는 기존 저수지의 유지용수 공급을 위한 운영, 유수지의 다목적 활용, 하천수 직접취수 제한 등이 있다. 지하수 분야의 대안으로는 지하철 용출수의 재이용, 지하수의 과다이용 제한, 침투증진시설의 설치 등이 있으며 대체수자원 분야의 대안으로는 하수처리수를 고도처리하여 유지용수로 재이용하는 것, 중소규모 하수처리장의 상류 설치, 대규모 사업장의 폐수를 고도처리하여 활용하는 것, 상수도의 이용 등이 있다. 이러한 여러 가지 대안들은 Walesh(1989)가 제안한 절차에 따라 기술가능성(technical feasibility), 경제성(economical efficiency), 환경성(environmental feasibility) 등을 정성적으로(qualitatively) 파악하여 실현가능한 대안을 선정하였다. 이렇게 선정된 대안들은 중유역별로 검토하여 효과가 있을 것으로 판단되는 대안들을 제시하는 예비타당성(Prefeasibility) 계획을 수립하였다. 이렇게 제시된 계획은 향후 과학적인 분석(세부평가방법)을 통해 대안을 평가하고 구체적인 타당성(feasibility) 계획을 수립하는데 토대가 될 것이다.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.109-115
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• 2014

The purpose of this study is to estimate the sediment volume concentration of the liquified-solid mixture which is included fine sediment fractions, according to the variance of the channel slope and the water supply. The numerical model was performed by using the Finite Differential Element Method (FDM) based on the equation for the mass conservation, momentum conservation and the equation of coarse sediment an fine sediment. In comparison of varying the channel slope, the deeper the channel slope, the inflection point of the sediment concentration was occurred rapidly. In comparison of variance of the water supply, as the water supply increases fluctuation with high sediment concentration. In this situation, debris flow changes to the turbulent flow and the sediment becomes to be floated. In comparison varying the length paved saturated sediment, the longer the length, the high concentration of sediment occurred, for the safety of the slope it is needed to check the possibility of the erosion in the slope by debris flow. The results of this study will provide useful information in predicting of the disaster by the liquified-solid mixture and in prevention of the debris flow with various the slope in the mountain side.

• The KIPS Transactions:PartD
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• v.9D no.6
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• pp.1017-1024
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• 2002

According as mobile computing environment is generalized by development of wireless networking technology and communication device, mobile host uses local cache for extensibility and early response time. and reduction of limited bandwidth. This time, between mobile host and mobile support station cache need consistency interested person of done data accordingly much techniqueses propose. Existent consistency techniques because detection based techniqueses are used mainly and broadcast periodic invalid message considering frequent disconnection. However, these techniqueses increase abort step through increase or delay of transmission message number by accuracy examination of data. Therefore, because mobile host deletes cached data, and extensity are decreased. Techniques that is proposed in this paper did to perform refering update frequency about object that page request or when complete update operation happens to solve these problem. Therefore, have advantage that response is fast because could run write intention declaration or update by update frequency electively asynchronously when update operation consists and abort step decreases. Also, improved extensity running delete or propagation electively according to update frequency about periodic invalid message gone since disconnection.

• Economic and Environmental Geology
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• v.52 no.3
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• pp.231-241
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• 2019

Kinematic analysis determines the stability of rock slope by analyzing the relationship between the slope face orientation and the discontinuity orientation. In this study, terrestrial LiDAR was used to obtain a large amount of discontinuity orientation data and then, the probabilistic characteristics of the orientation data obtained using terrestrial LiDAR were analyzed. Subsequently, the probabilistic kinematic analysis was carried out using the discontinuity orientations generated randomly from Fisher function in Monte Carlo simulation. In addition, the probabilistic kinematic analysis was also performed using the actual orientation data obtained from the terrestrial LiDAR to compare their results. Consequently, the results of both probabilistic analyses showed similar results. Therefore, if sufficient orientation data are provided by other means such as terrestrial LiDAR, the probabilistic analysis will show reasonable results using the actual field data without randomly generating orientation data. In addition, the deterministic kinematic analysis was also carried out using representative orientation of discontinuity sets. The analysis result of the probabilistic analysis showed similar results with the deterministic analysis because the dispersion of the discontinuity orientations in a joint set is not large.

• Korean Journal of Remote Sensing
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• v.32 no.2
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• pp.141-153
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• 2016

Reliable assessment of Land Use and Land Cover (LULC) changes greatly improves many practical issues in hydrography, socio-geographical research such as the observation of erosion and accretion, coastal monitoring, ecological effects evaluation. Remote sensing imageries can offer the outstanding capability to monitor nature and extent of land and associated changes over time. Nowadays accurate analysis using remote sensing imageries with high spatio-temporal resolution is required for environmental monitoring. This study develops a methodology of mapping and change detection in LULC by using classified Korea Multi-Purpose Satellite-2 (KOMPSAT-2) multispectral imageries at Jeonbuk and Jeonnam provinces including protected tidal flats located in the west coasts of Korean peninsula from 2008 to 2015. The LULC maps generated from unsupervised classification were analyzed and evaluated by post-classification change detection methods. The LULC assessment in Jeonbuk and Jeonnam areas had not showed significant changes over time although developed area was gradually increased only by 1.97% and 4.34% at both areas respectively. Overall, the results of this study quantify the land cover change patterns through pixel based analysis which demonstrate the potential of multispectral KOMPSAT-2 images to provide effective and economical LULC maps in the coastal zone over time. This LULC information would be of great interest to the environmental and policy mangers for the better coastal management and political decisions.

• Journal of the Korean earth science society
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• v.32 no.3
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• pp.249-264
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• 2011

A multi-Gaussian kriging approach extended to space-time domain is presented for uncertainty modeling as well as time-series mapping of environmental variables. Within a multi-Gaussian framework, normal score transformed environmental variables are first decomposed into deterministic trend and stochastic residual components. After local temporal trend models are constructed, the parameters of the models are estimated and interpolated in space. Space-time correlation structures of stationary residual components are quantified using a product-sum space-time variogram model. The ccdf is modeled at all grid locations using this space-time variogram model and space-time kriging. Finally, e-type estimates and conditional variances are computed from the ccdf models for spatial mapping and uncertainty analysis, respectively. The proposed approach is illustrated through a case of time-series Particulate Matter 10 ($PM_{10}$) concentration mapping in Incheon Metropolitan city using monthly $PM_{10}$ concentrations at 13 stations for 3 years. It is shown that the proposed approach would generate reliable time-series $PM_{10}$ concentration maps with less mean bias and better prediction capability, compared to conventional spatial-only ordinary kriging. It is also demonstrated that the conditional variances and the probability exceeding a certain thresholding value would be useful information sources for interpretation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.228-237
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• 2021

In those day, the Busan local government had instituted a rule to support and enhance competition as well as improve respect for the ship management industry. This study aims to extract the cause factors to enhance such competition using intuitionistic decision making trial and evaluation laboratory (DEMATEL) and interpretive structural modeling (ISM) methods. First, eight factors were extracted from the specifications in the Ship Management Industry Development Act. Second, the intuitionistic fuzzy number was converted to a crisp number using the standard fuzzy number. Third, the influence relationship was analyzed using DEMATEL, and the priority ranks for the factors are determined using ISM. From the results of the impact relationship analysis, the three main cause factors were determined as improvement of technical ship management capability, improvement of expertise of manpower for onshore management, and improvement of the quality of the Korean seafarer. The priorities under the ISM method, in descending order, were as follows: improvement of the quality of Korean seafarers, improvement of professionalism among the manpower for shore management, improvement of technical ship management capability, improvement of commercial ship management capability, establishment of a comprehensive information system, improvement of the working conditions and employment environment for seafarers, financial support such as overseas orders, and strengthening the availability of foreign seafarers. Therefore, it is necessary to prioritize policy promotion based on these factors, especially the top three, as these have the highest impact.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.345-351
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• 2013

The IWRAP program (Inland Waterway Risk Assessment Program) is a useful program for risk assessment of a waterway. However, in the basic version, the function which is used to import AIS data is not included. So users have to prepare the data and input to the program manually. And not all waterways have enough statistical data about passing vessels especially in developing countries as Vietnam. This paper studies the development of a program to pre-process AIS data for using the IWRAP Mk2 program basic version. In addition, it provides users basic information about marine traffic in a waterway such as routes layout, number of passages at a gate classified by type, size and time. The developed program, named TOAIS (Total AIS), was successfully used to pre-process AIS data collected in the Vung Tau waterway-Vietnam. As a result, the IWRAP Mk2 program basic version using data pre-processed from TOAIS could effectively assess the risk of collision in this waterway.

• Journal of the Korean GEO-environmental Society
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• v.14 no.11
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• pp.5-12
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• 2013

The purpose of this study is to estimate the behavior and the mechanism of debris flow at the end of mountain side when a berm was set on the inclined plane. The numerical model was performed by using the Finite Difference Method(FDM) based on the equation for the mass conservation and momentum conservation. In order to measure the behavior of the debris flow, the debris flow of a straight channel slope and the debris flow of channel slope with 3 types of berms were compared. First, the flow discharge and the sediment volume concentration at the downstream of the channel slope, depending on the various berm width and the different inflow discharges at the upstream of the channel were analyzed. The longer the berm width, the flow discharge at the downstream of the channel was decreased and the high flow fluctuation was reduced by a berm. And it means that a berm can effect for the delay of the debris flow. Through Root Mean Square ratio(RMS) comparison, the flow discharge of the channel slope with a berm was lower than that of a straight channel slope. The longer the berm width, for the sediment volume concentration, an inflection point did not show but mild curve. Because the low sediment concentration with water mixture by a berm continuously flow at the downstream end, it will be effect for reducing the disaster caused by debris flow. The results of this study will provide useful information in predicting and preventing disaster caused by the debris flow.