• Title/Summary/Keyword: Macroscopic Characteristics

Search Result 252, Processing Time 0.024 seconds

Exploring Delays of The Mega Construction Project: The Case of Korea High Speed Railway (대형 건설사업의 공기지연분석: 경부고속철도 건설사업을 중심으로)

  • Han, Seung Heon;Yun, Sung Min;Lee, Sang Hyun
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.26 no.5D
    • /
    • pp.839-848
    • /
    • 2006
  • Korea has become the 5th country to own and operate the high speed railroad in 2004. However, there were many difficulties until Koreans enjoy the first bullet train service with the average hourly speed of 300km. The high speed railroad requires elevated quality standards differently from the traditional railways. In addition to the technical difficulties, the construction project itself was an unpleasant case with huge delays and cost overruns mainly due to the lack of experiences, deficiency of owner$^{\circ}{\O}$s role, and increase of public resistances triggered by environmental concerns. This paper analyzes the reasons for delays on this mega-project. With respect to the characteristics of the whole project level, it is very complicated/linear project, whose total length is around 412 km with the composition of various sections in the route of the railway which have basically different conditions. For that reason, the analysis is performed in both macro and micro level. First, macroscopic analysis is performed to find critical subdivisions in the railway route that induces the significant delay in the opening due date. Then, microscopic analysis is followed to quantify the causes and effects of delays focused on these critical subdivisions in more detailed way. Finally, this paper provides lessons learned from this project to avoid the decisive delays in performing the similar large-scaled projects.

A Policy Proposal for the Safety of Inland Water Ships (내수면 선박의 안전성 확보를 위한 정책 제언)

  • Byung-Hwa Song;Hong-Hoon Lee;Chang-Hyun Lee
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.29 no.4
    • /
    • pp.332-337
    • /
    • 2023
  • Korea is not only surrounded by the sea on three sides, but also has national and local rivers extending 26,843 km, so it has a geographical feature in which abundant sea and inland water surface coexist. As the number of ships operating in the inland waters is continuously increasing due to the improvement of national income, the risk of ship accidents and human casualties in the inland waters is also increasing. In this study, a macroscopic plan for the safety management of inland water ships was presented through investigation of inland water related laws and operation status analysis. As an improvement plan, as a hardware infrastructure it is proposed to secure sufficient inland water fire-boats to secure the golden time for early response to accidents and lifesaving, and to operate an institution specializing in the prevention of inland water ships accidents. And as a software infrastructure, establish departure control standards for inland water ships and the safety diagnosis system currently applied only to sea going ships, the introduction of a system tailored to the characteristics of inland water ships. The proposed inland water safety management policy is expected to contribute to the preparation of prompt and systematic countermeasures in the event of an inland water ship accident, and it is hoped that it will serve as an opportunity to continue to pay attention to safety-related research on inland water ships, which was briefly activated after the sinking of M/V Sewol.

Vehicle Acceleration and Vehicle Spacing Calculation Method Used YOLO (YOLO기법을 사용한 차량가속도 및 차두거리 산출방법)

  • Jeong-won Gil;Jae-seong Hwang;Jae-Kyung Kwon;Choul-ki Lee
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.23 no.1
    • /
    • pp.82-96
    • /
    • 2024
  • While analyzing traffic flow, speed, traffic volume, and density are important macroscopic indicators, and acceleration and spacing are the important microscopic indicators. The speed and traffic volume can be collected with the currently installed traffic information collection devices. However, acceleration and spacing data are necessary for safety and autonomous driving but cannot be collected using the current traffic information collection devices. 'You Look Only Once'(YOLO), an object recognition technique, has excellent accuracy and real-time performance and is used in various fields, including the transportation field. In this study, to measure acceleration and spacing using YOLO, we developed a model that measures acceleration and spacing through changes in vehicle speed at each interval and the differences in the travel time between vehicles by setting the measurement intervals closely. It was confirmed that the range of acceleration and spacing is different depending on the traffic characteristics of each point, and a comparative analysis was performed according to the reference distance and screen angle to secure the measurement rate. The measurement interval was 20m, and the closer the angle was to a right angle, the higher the measurement rate. These results will contribute to the analysis of safety by intersection and the domestic vehicle behavior model.

LNG Gas Demand Forecasting in Incheon Port based on Data: Comparing Time Series Analysis and Artificial Neural Network (데이터 기반 인천항 LNG 수요예측 모형 개발: 시계열분석 및 인공신경망 모형 비교연구)

  • Beom-Soo Kim;Kwang-Sup Shin
    • The Journal of Bigdata
    • /
    • v.8 no.2
    • /
    • pp.165-175
    • /
    • 2023
  • LNG is a representative imported cargo at Incheon Port and has a relatively high contribution to the increase/decrease in overall cargo volume at Incheon Port. In addition, in the view point of nationwide, LNG is the one of the most important key resource to supply the gas and generate electricity. Thus, it is very essential to identify the factors that have impact on the demand fluctuation and build the appropriate forecasting model, which present the basic information to make balance between supply and demand of LNG and establish the plan for power generation. In this study, different to previous research based on macroscopic annual data, the weekly demand of LNG is converted from the cargo volume unloaded by LNG carriers. We have identified the periodicity and correlations among internal and external factors of demand variability. We have identified the input factors for predicting the LNG demand such as seasonality of weekly cargo volume, the peak power demand, and the reserved capacity of power supply. In addition, in order to predict LNG demand, considering the characteristics of the data, time series prediction with weekly LNG cargo volume as a dependent variable and prediction through an artificial neural network model were made, the suitability of the predictions was verified, and the optimal model was established through error comparison between performance and estimates.

Comparative Analysis of Conceptual and Algorithmic Problem Solving Ability on Boyle's Law and Charles's Law in Middle School 1st Grade Students (보일의 법칙과 샤를의 법칙에 대한 중학교 1학년 학생들의 개념 문제 해결력과 수리 문제 해결력 비교 분석)

  • Park, Jin-Sun;Kim, Dong-Jin;Park, Se-Yeol;Hwang, Hyun-Sook;Park, Kuk-Tae
    • Journal of the Korean Chemical Society
    • /
    • v.55 no.6
    • /
    • pp.1042-1055
    • /
    • 2011
  • The purpose of this study was to compare the conceptual and algorithmic problem solving ability on Boyle's law and Charles's law according to cognitive levels and characteristics of students in middle school 1st grade students. For this study, questionnaire items of conceptual and algorithmic problem solving ability were developed. and the problem solving ability according to cognitive levels and characteristics of students was compared. The long-term memory effect in conceptual and algorithmic problem solving ability according to cognitive levels was investigated, and problem solving process were analyzed by questionnaire items. In the results of this study, conceptual problem solving ability was higher than algorithmic problem solving ability in all cognitive levels. There was statistically significant difference in concrete operational period and transitional period students. In comparison of the long-term memory effect in conceptual and algorithmic problem solving ability, formal operational period students had the long-term memory effect. There was no statistically significant difference in the conceptual and algorithmic problem solving ability according to private education among the characteristics of students. But there was statistically significant difference in the problem solving ability according to experiences of the scientific activities and hopes to related scientific careers. From results of analysis of problem solving process, it is known that the students had a tendency to just remember macroscopic phenomena and to solve the problems without understanding the concepts. Therefore, teaching and learning strategy is necessary to replace unscientific concepts by the scientific concepts through identifying students's unscientific concepts in advance.

Analyze of I-V Characteristics and Amorphous Sturcture by XRD Patterns (XRD 패턴에 의한 비정질구조와 I-V 특성분석)

  • Oh, Teresa
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.20 no.7
    • /
    • pp.16-19
    • /
    • 2019
  • A thinner film has superior electrical properties and a better amorphous structure. Amorphous structures can be effective in improving conductivity through a depletion effect. Research is needed on the Schottky contact, where potential barriers are formed, as a way to identify these characteristics. $SiO_2/SnO_2$ thin films were prepared to examine the amorphous structure and Schottky contact, $SiO_2$ thin films were prepared using Ar = 20 sccm. $SnO_2$ thin films were deposited using mixed gas with a flow rate of argon and oxygen at 20 sccm, and $SnO_2$ thin films were added by magnetron sputtering and treated at $100^{\circ}C$ and $150^{\circ}C$. To identify the conditions under which the amorphous structure was constructed, the XRD patterns were investigated and C-V and I-V measurements were taken to make Al electrodes and perform electrical analysis. The depletion layer was formed by the recombination of electrons and holes through the heat treatment process. $SiO_2/SnO_2$ thin films confirmed that the pores were well formed when heat treated at $100^{\circ}C$ and an electric current was applied over the micro area. An amorphous $SiO_2/SnO_2$ thin film with heat treatment at $100^{\circ}C$ showed no reflection at $33^{\circ}\;2{\theta}$ in the XRD pattern, and a reflection at $44^{\circ}2\;{\theta}$. The macroscopic view (-30 V

Development of A Network loading model for Dynamic traffic Assignment (동적 통행배정모형을 위한 교통류 부하모형의 개발)

  • 임강원
    • Journal of Korean Society of Transportation
    • /
    • v.20 no.3
    • /
    • pp.149-158
    • /
    • 2002
  • For the purpose of preciously describing real time traffic pattern in urban road network, dynamic network loading(DNL) models able to simulate traffic behavior are required. A number of different methods are available, including macroscopic, microscopic dynamic network models, as well as analytical model. Equivalency minimization problem and Variation inequality problem are the analytical models, which include explicit mathematical travel cost function for describing traffic behaviors on the network. While microscopic simulation models move vehicles according to behavioral car-following and cell-transmission. However, DNL models embedding such travel time function have some limitations ; analytical model has lacking of describing traffic characteristics such as relations between flow and speed, between speed and density Microscopic simulation models are the most detailed and realistic, but they are difficult to calibrate and may not be the most practical tools for large-scale networks. To cope with such problems, this paper develops a new DNL model appropriate for dynamic traffic assignment(DTA), The model is combined with vertical queue model representing vehicles as vertical queues at the end of links. In order to compare and to assess the model, we use a contrived example network. From the numerical results, we found that the DNL model presented in the paper were able to describe traffic characteristics with reasonable amount of computing time. The model also showed good relationship between travel time and traffic flow and expressed the feature of backward turn at near capacity.

The post-epic characteristics in Jan Lauwers' theatre -, and - (얀 라우어스(Jan Lauwers) 공연의 탈서사적 특징들 -<이사벨라의 방(Isabella's Room)>, <랍스터 가게(The Lobster Shop)>, <사슴의 집(Deer House)>을 중심으로-)

  • Nam, Jisoo
    • Journal of Korean Theatre Studies Association
    • /
    • no.48
    • /
    • pp.447-484
    • /
    • 2012
  • This study aims to analyze the characteristics of post-epic theatre in the Belgian theatre director Jan Lauwers' trilogy titled in "Happy Face/Sad Face": (2004), (2006) and (2008). I regard that it played a very important junction for him to create his own theatrical style compared to earlier years. From this period, Lauwers has tried to create his original plays in order to concentrate the story of our era and has showed to combine a variety of media such as dance, installation, video, singing etc. In this context, I would like to study his own theatricality from the three perspectives of dramaturgy, directing and acting largely based on Hans-Thies Lehmann's theory of post-epic theatre, who pointed out the significance of Lauwer's theatrical leading role very early. First, from the dramaturgical point of view, we need to pay attention to the theme of translunary death; where the living and the dead coexist on the stage. In fact, death is the theme that Lauwers has been struggling to research for quite long time. In his trilogy, the dead never exits the stage. The dead, who is not a representative tragic character, even meddles the things among or with the living and provide comments to people. As a consequence, it happens to reduce a dramaturgical strong tension, leads depreciation of suspense and produces humanism in a way. This approach helps to create his unique comical theatrical atmosphere even though he deals with the contemporary tragic issues such as war, horror and death. Second, from the directing point of view, it is worth to take a look at the polyphonic strategy in terms to applying various media. Among all the things, the arts of dancing and singing in chorus are actively applied in Lauwer's trilogy. The dance is used in individual and microscopic way, on the other hand, singing shows collective and is a macroscopic quality. The dance is the representing media to show Lauwer's simultaneous microscopic mise-en-scene. While main plot takes place around the center-stage, actors perform a dance around the off-centered stage. Instead of exiting from the stage during the performance, the actors would continue dance -sometimes more like movements- around the off-centered stage. This not only describes the narrative, but also shows how each character is engaged to the main plot or incident, and how they look into it as a character. Its simultaneous microscopic mise-en-scene intends to function such as: showing a variety moments of lives, amplifying some moments or incidents, revealing character's emotion, creating illusionary theatrical atmosphere and so on. Meanwhile, singing simple lyrics and tunes are an example of the media to stimulate the audiences' catharsis. As the simple melody lingers in the audiences' mind, it ends up delivering a theatrical message or theme after the performance. This message would be transferred from the singing in chorus functions as a sort of leitmotive in order to make an impression to the audience. This not only richens their emotion but also creates an illusionary effect. Third, from the acting perspective, I'd like to point out the "detachment" aesthetic which Lehmann has pointed out. The actors never go deep into the drama by consistently doing recognize a theatrical illusion. The audience happens to pay attention to their presence through the actor's deliberate gesture, business, movement, rhythm, language, dance etc. The actors are against forming closed action by speaking in various languages or by revealing deliberately stage directions or acts, and by creating expressive mise-en-scene with multiple media. As a consequent, the stage can be transformed to not a metaphoric but a metonymic place. These actions are the ultimate intention for a direct effect to the audience. So to speak, Lauwers uses the anti-illusionary theatrical method: the scenes of fantastic death, interruption of singing and dance, speaking many kinds of languages, acting in detachment-status and so on. These strategies function to make cracks in spectators' desire who has a desire to construct a linear narrative. I'd like to say that it is the numerous potentiality to let the reality penetrate though and collide the reality with a fiction. By doing so, it induces for spectators to see the reality in the fiction. As Lehmann says, "when theatre presents itself as a sketch and not as a finished painting, the spectators are given the chance to feel their own presence, to reflect on it, and to contribute to the unfinished character themselves". In this sense the spectators can perform an objective criticism on our society and world in Lauwer's theatre because there are a number of gaps and cracks in his theatrical illusion where reality can penetrate. This is also the point that we can find out the artists' responsibility in this era of our being.

The Effects of Technological Competitiveness by Country on The Increase of Unicorn Companies (국가별 기술경쟁력이 유니콘기업 증가에 미치는 영향에 관한 연구)

  • Kyu Hoon Cho;Dong Woo Yang
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.19 no.1
    • /
    • pp.55-73
    • /
    • 2024
  • Unicorn companies are attracting attention around the world as they are recognized for their high corporate value in a short period of time as an innovative business models. Their growth process presents good lessons for the startup ecosystem and have a positive impact on national economic development and job creation. However, previous studies related to unicorn companies are focused on 'event studies' and 'case studies' such as characteristics of founders, environmental factors, business models and success/failure cases of companies already recognized as unicorns rather than a multifaceted approach. The occurrence of unicorn companies and Macroscopic analysis of related factors is lacking. Against this background, this study are considering the characteristics of unicorns examined through previous research and the current status unicorns with a high proportion of technology companies, the purpose was to analyze the impact of the country's technological competitiveness, such as 'technology human resource index', 'R&D index', and 'technology infrastructure index', on the increase in unicorn companies. For statistical analysis, data published by various international organizations, the Bank of Korea, and Statistics Korea from 2017 to 2020 and unicorn company data compiled by CB Insights were used as panel data for 44 countries to be tested by multiple regression analysis. As a result of the study, it was confirmed that the number of science majors had a positive (+) effect on the increase of unicorn companies in the case of technology human resource index, and in the case of R&D index, the total amount of R&D investment had a positive (+) effect on the increase of unicorn companies, while the number of Triad Patents Families and the number of scientific and technological papers published had a negative (-) effect on the increase of unicorn companies. Finally, in the case of technology infrastructure index, it was confirmed that the number of the world's 500th-ranked universities had a positive (+) effect on the increase of unicorn companies. This study is the first to reveal the causal relationship between national technological competitiveness and unicorn company growth based on country-specific and time-series empirical data, which were insufficiently covered in previous studies. and compared to the UN's ranking of the global industrial competitiveness index and the OECD's total R&D investment by country, Korea is considered to have technological and growth potential, while the number of unicorn companies driving growth as leaders of the innovative economy is relatively small, so the research results can be used when establishing policies to discover and foster unicorn companies in the future.

  • PDF

Adsorption of Arsenic on Goethite (침철석(goethite)과 비소의 흡착반응)

  • Kim, Soon-Oh;Lee, Woo-Chun;Jeong, Hyeon-Su;Cho, Hyen-Goo
    • Journal of the Mineralogical Society of Korea
    • /
    • v.22 no.3
    • /
    • pp.177-189
    • /
    • 2009
  • Iron (oxyhydr)oxides commonly form as secondary minerals of high reactivity and large surface area resulting from alteration and weathering of primary minerals, and they are efficient sorbents for inorganic and organic contaminants. Accordingly, they have a great potential in industrial applications and are also of substantial interest in environmental sciences. Goethite (${\alpha}$-FeOOH) is one of the most ubiquitous and stable forms of iron (oxyhydr)oxides in terrestrial soils, sediments, and ore deposits, as well as a common weathering product in rocks of all types. This study focused on adsorption reaction as a main mechanism in scavenging arsenic using goethite. Goethite was synthesized in the laboratory to get high purity, and a variety of mineralogical and physicochemical features of goethite were measured and related to adsorption characteristics of arsenic. To compare differences in adsorption reactions between arsenic species, in addition, a variety of experiments to acquire adsorption isotherm, adsorption edges, and adsorption kinetics were accomplished. The point of zero charge (PZC) of the laboratory-synthesized goethite was measured to be 7.6, which value seems to be relatively higher, compared to those of other iron (oxyhydr)oxides. Its specific surface area appeared to be $29.2\;m^2/g$ and it is relatively smaller than those of other (oxyhydr)oxides. As a result, it was speculated that goethite shows a smaller adsorption capacity. It is likely that the affinity of goethite is much more larger for As(III) (arsenite) than for As(V) (arsenate), because As(III) was observed to be much more adsorbed on goethite than As(V) in equivalent pH conditions. When the adsorption of each arsenic species onto goethite was characterized in various of pH, the adsorption of As(III) was largest in neutral pH range (7.0~9.0) and decreased in both acidic and alkaline pH conditions. In the case of As(V), the adsorption appeared to be highest in the lowest pH condition, and then decreased with an increase of pH. This peculiarity of arsenic adsorption onto goethite might be caused by macroscopic electrostatic interactions due to variation in chemical speciation of arsenic and surface charge of goethite, and also it is significantly affected by change in pH. Parabolic diffusion model was adequate to effectively evaluate arsenic adsorption on goethite, and the regression results show that the kinetic constant of As(V) is larger than that of As(III).