• Korean Institute of Interior Design Journal
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• v.27 no.1
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• pp.3-11
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• 2018

The number of shared offices has increased and changed within the flow of the era into various forms in recent days. Co-working spaces and related shared space businesses are growing fast, keeping pace with the trend recently. It is confirmed that the need of spaces grew 180% since 2015 to 2017. Most of the shared offices in Seoul are placed in Gangnam circle, it is verified that shared office is providing work, space, and community by visiting cases of foreign companies, domestic companies, local companies. Meanwhile, shared space can be categorized into serviced office, co-working space, virtual office, and daily office. It is to consider various target levels by leasing service or the difference of costs. It is divided into forms of dispersion, circulation, and concentration and is planned to increase the utilization of communities' traffic according to the allocation of shared office. The business is conducted network-centered. During the process of communication, members can get chances to exchange and build communities. They are making business ecosystem which they can coexist and grow together. Shared offices have a view of a solution to empty rooms and will last for a while, and it is expected that co-working system be settled as office space and giving people sense of belonging on their workspace.

• Fashion & Textile Research Journal
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• v.11 no.1
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• pp.84-92
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• 2009

The purpose of this study was to examine the facilities, the current status, and the problems of Korean Exhibition Industry and to provide its future direction based on analysis of the characteristics and the recent trend of German Exhibition Industry. Data were obtained from previous research papers, periodicals, magazines, and newspapers. Also, statistical data provided by AUMA(Ausstellungs- und Messe- Ausschuss der Deutschen Wirtschaft e.V.), Association of Korean Exhibition Industries, and Global Exhibition Portal were used. In the result part of this study, various issues such as similarities and differences between Korean and German Exhibition Industry and problems of Korean Exhibition Industry were discussed. The strategies to improve the competitiveness of Korean Exhibition Industry were suggested. They are as follows ; development of global and specialized exhibitions, training of professional human resources for exhibition, formulating of aggressive and powerful oversee marketing, formation of oversee network, improving of laws, regulation and system in such a way to meet the realistic needs of exhibition, building of infrastructure such as roads, traffic networks and accomodations, raise of the Korea image and strengthen of quality of exhibition service.

• Journal of Korean Society of Transportation
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• v.31 no.5
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• pp.37-47
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• 2013

This Study analyzed the electric car effect on the Korea Expressway System in terms of year 2020 $CO_2$ emission. The analysis was based on the green car dissemination goal by the government and year 2010 emission statistics. Major contents performed in the study area were as follows. First, the greenhouse gases emitted from the highways were found to be approximately 17.3 million tons of $CO_2$ as of 2010. Analysis showed the emission would be 17.4 million tons in 2015 and 16.2 million tons in 2020. The results in the pattern reflect the effect of O/D on the KTBD and the trend of traffic increase from 2015 to 2020 followed by decrease in 2020. Second, in the case of greenhouse gas emission with the anticipated supply of electric cars, the amount of emission in 2015 will be 17.1 million tons, which is about 2.0% reduction compared to the lack of introduction of electric cars. The analysis also showed that in 2020, the amount of emission will be 14.2 million tons, which indicates the effect of reduction is 12.8% compared to non implementation of the program.

• Smart Structures and Systems
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• v.10 no.2
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• pp.131-154
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• 2012

In this paper, it is aimed to determine the seismic behaviour of highway bridges by nondestructive testing using ambient vibration measurements. Eynel Highway Bridge which has arch type structural system with a total length of 216 m and located in the Ayvaclk county of Samsun, Turkey is selected as an application. The bridge connects the villages which are separated with Suat U$\breve{g}$urlu Dam Lake. A three dimensional finite element model is first established for a highway bridge using project drawings and an analytical modal analysis is then performed to generate natural frequencies and mode shapes in the three orthogonal directions. The ambient vibration measurements are carried out on the bridge deck under natural excitation such as traffic, human walking and wind loads using Operational Modal Analysis. Sensitive seismic accelerometers are used to collect signals obtained from the experimental tests. To obtain experimental dynamic characteristics, two output-only system identification techniques are employed namely, Enhanced Frequency Domain Decomposition technique in the frequency domain and Stochastic Subspace Identification technique in time domain. Analytical and experimental dynamic characteristic are compared with each other and finite element model of the bridge is updated by changing of boundary conditions to reduce the differences between the results. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of highway bridges. After finite element model updating, maximum differences between the natural frequencies are reduced averagely from 23% to 3%. The updated finite element model reflects the dynamic characteristics of the bridge better, and it can be used to predict the dynamic response under complex external forces. It is also helpful for further damage identification and health condition monitoring. Analytical model of the bridge before and after model updating is analyzed using 1992 Erzincan earthquake record to determine the seismic behaviour. It can be seen from the analysis results that displacements increase by the height of bridge columns and along to middle point of the deck and main arches. Bending moments have an increasing trend along to first and last 50 m and have a decreasing trend long to the middle of the main arches.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.4
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• pp.821-830
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• 2017

The internet is an important infra resource that it controls the economy and society of our country. Also, it is providing convenience and efficiency of the everyday life. But, a case of various are occurred through an using vulnerability of an internet infra resource. Recently various attacks of unknown to the user are an increasing trend. Also, currently system of security control is focussing on patterns for detecting attacks. However, internet threats are consistently increasing by intelligent and advanced various attacks. In recent, the darknet is received attention to research for detecting unknown attacks. Since the darknet means a set of unused IP addresses, no real systems connected to the darknet. In this paper, we proposed an algorithm for finding black IPs through collected the darknet traffic based on a statistics data of port information. The proposed method prepared 8,192 darknet space and collected the darknet traffic during 3 months. It collected total 827,254,121 during 3 months of 2016. Applied results of the proposed algorithm, black IPs are June 19, July 21, and August 17. In this paper, results by analysis identify to detect frequency of black IPs and find new black IPs of caused potential cyber threats.

• Tunnel and Underground Space
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• v.11 no.4
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• pp.319-327
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• 2001

Introduction of new design tools has been required to optimally design and operate the ventilation system of long vehicle tunnels.. The demand has led to wide spread use of the simulation technique throughout the would to analysis the dynamic relationship among the variables associated with vehicle tunnel ventilation. This paper aims at performing on-site study at local tunnels to test the applicability of NETVEN, a simulation model vehicle tunnel ventilation. The study was carried out at four urban as well as highway tunnels model of vehicle tunnel ventilation. The study was carried out at four urban as well as highway tunnels employing different ventilation systems as well as traffic methods. There were some discrepancies sound between the simulation output and measurements and the following four factors are considered to mainly cause those disagreement. (1) The real situation shows distinctive transient and retarding characteristics with respect to air flow and contaminant dispersion, while ventilation forces are not steady-state and in particular those traffic and climatic variables show significant instantaneous variation. (3) Near the exit portal, the CO levels show bigger differences. The general trend is that data with higher CO concentrations carry bigger discrepancies. Turbulent diffusion is though to be the main reason for it and also contribute to the fact hat the highest CO concentrations are found at the locations somewhat inward, not at the exit portals. (4) Higher traffic rate results in higher discrepancies of ventilation velocity. Along with the exhaust characteristics, the vehicle aerodynamic characteristics need to be studied continuously in order to reduce the velocity disagreement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5301-5323
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• 2017

Small cell deployment offers a low-cost solution for the boosted traffic demand in heterogeneous cellular networks (HCNs). Besides improved spatial spectrum efficiency and energy efficiency, future HCNs are also featured with the trend of network architecture convergence and feasibility for flexible mobile applications. To achieve these goals, dual connectivity (DC) is playing a more and more important role to support control/user-plane splitting, which enables maintaining fixed control channel connections for reliability. In this paper, we develop a tractable framework for the downlink SINR analysis of DC assisted HCN. Based on stochastic geometry model, the data-control joint coverage probabilities under multi-frequency and single-frequency tiering are derived, which involve quick integrals and admit simple closed-forms in special cases. Monte Carlo simulations confirm the accuracy of the expressions. It is observed that the increase in mobility robustness of DC is at the price of control channel SINR degradation. This degradation severely worsens the joint coverage performance under single-frequency tiering, proving multi-frequency tiering a more feasible networking scheme to utilize the advantage of DC effectively. Moreover, the joint coverage probability can be maximized by adjusting the density ratio of small cell and macro cell eNBs under multi-frequency tiering, though changing cell association bias has little impact on the level of the maximal coverage performance.

• Industry Promotion Research
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• v.8 no.3
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• pp.9-17
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• 2023

The purpose of this study is to look for the trends and rates of change of major passenger modes such as railway, subway, domestic shipping, domestic airline, international shipping and international airline. The data used were selected from the KOSIS, "Domestic Statistics, Statistics by Subject, Transportation and Logistics". The analysis period was 22 years from 1999 to 2020, and the annual rate of change from the previous year was calculated. In descriptive statistics, international shipping and international airlines showed relatively high volatility, whereas railway and subway showed low volatility. In the rise rate analysis, international air and international shipping dropped significantly from 539% and 368% in 2019 to 85% and 20% in 2020 due to Corona. International airline and international shipping fell significantly in 2020, but we expect them to rise again as the shock of Corona disappears in the future. Therefore, it seems that we need a project to prepare for this. International air and international shipping are expected to continue their upward trend as international trade picks up again and international travel regains its momentum.

• Journal of Advanced Navigation Technology
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• v.25 no.6
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• pp.476-483
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• 2021

In order to maintain the safety of the airspace with ever increasing traffic volume, it is necessary to thoroughly analyze the collision risk with the current data. In this study, collision risk analysis was conducted using Detect and Avoid (DAA) Well-Clear (DWC) metrics, risk induces developed for the DAA systems of unmanned aerial vehicles. All flights in year 2019 that flew within the Incheon Flight Information Region (FIR) boundary were analyzed using the recorded Automatic Dependent Surveillance-Broadcast(ADS-B) data. High risk regions as well as trends by airports and seasons were identified. The results indicate that the risk is higher around the congested area near Incheon International Airport and Gimpo International Airport. Seasonally, the risk was highest in August that coincides with the Summer vacation period. The result will be useful for the baseline data for various aviation safety enhancement activities such as revision of routes and procedures and training of the field specialists.

• Journal of the Korean Society of Safety
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• v.38 no.6
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• pp.50-59
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• 2023

As the diversity of disasters continues to increase, the concept of "complex disasters" has gained prominence in various policies and studies related to disaster management. However, there has been a certain limitation in the availability of the systematic statistics or data in advancing policies and research initiatives related to complex disasters. This study aims to analyze the macro-level characteristics of the complex disasters that have occurred domestically utilizing a 30-year span of a news data. Initially, we categorize the complex disasters into the three types: "Natural disaster-Natural disaster", "Natural disaster-Social disaster", and "Social disaster-Social disaster". As a result, the "natural diaster-social disaster" type is the most prevalent. It is noted that "natual disaster-natural disaster" type has increased significantly in recent 10 years (2011-2020). In terms of specific disaster types, "Storm and Flood", "Collapse", "Traffic Accident", "National Infrastructure Paralysis", and "Fire⋅Explosion" occur the most in conjunction with other disasters in a complex manner. It has been observed that the types of disasters co-ocuuring with others have become more diverse over time. Parcicularly, in recent 10 years (2011-2020), in addition to the aforementioned five types, "Heat Wave", "Heavy Snowfall⋅Cold Wave", "Earthquake", "Chemical Accident", "Infectious Disease", "Forest Fire", "Air Pollution", "Drought", and "Landslide" have been notable for their frequent co-occurrence with other disasters. These findings through the statistical analysis of the complex disasters using long-term news data are expected to serve as crucial data for future policy development and research on complex disaster management.