• Structural Engineering and Mechanics
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• v.38 no.1
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• pp.39-63
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• 2011

Referring to the formulation of physical stochastic optimal control of structures and the scheme of optimal polynomial control, a nonlinear stochastic optimal control strategy is developed for a class of structural systems with hysteretic behaviors in the present paper. This control strategy provides an amenable approach to the classical stochastic optimal control strategies, bypasses the dilemma involved in It$\hat{o}$-type stochastic differential equations and is applicable to the dynamical systems driven by practical non-stationary and non-white random excitations, such as earthquake ground motions, strong winds and sea waves. The newly developed generalized optimal control policy is integrated in the nonlinear stochastic optimal control scheme so as to logically distribute the controllers and design their parameters associated with control gains. For illustrative purposes, the stochastic optimal controls of two base-excited multi-degree-of-freedom structural systems with hysteretic behavior in Clough bilinear model and Bouc-Wen differential model, respectively, are investigated. Numerical results reveal that a linear control with the 1st-order controller suffices even for the hysteretic structural systems when a control criterion in exceedance probability performance function for designing the weighting matrices is employed. This is practically meaningful due to the nonlinear controllers which may be associated with dynamical instabilities being saved. It is also noted that using the generalized optimal control policy, the maximum control effectiveness with the few number of control devices can be achieved, allowing for a desirable structural performance. It is remarked, meanwhile, that the response process and energy-dissipation behavior of the hysteretic structures are controlled to a certain extent.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.4
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• pp.456-462
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• 2014

In this paper, we present a deployable bio-inspired robot called the Pillbot-light, which utilizes a safe autonomous navigation system. The Pillbot-light is mounted the station robot, and can be operated in a disaster relief operation or military operation. However, the Pilbot-light has a challenge to navigate autonomously because the Pilbot-light cannot be equipped with various sensors. As a result, we propose a new robot system for autonomous navigation that the station robot controls Pillbot-light equipped with vision camera and CPU of high performance. This system detects obstacles based on the edge extraction using vision camera. Also, it cannot only achieve path planning using the hazard cost function, but also localization using the Particle Filter. And this system is verified by simulation and experiment.

• Architectural research
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• v.20 no.3
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• pp.83-92
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• 2018

Recently, there has been inter-Korean exchanges are active, in company with an assertive international activity with North Korea and inter-Korean Summits. Thus, there is a growing possibility of Korean reunification. However, when the unification situation occurs, population inflow by North Korean residents will be expected, and it will be necessary to prepare a housing supply strategy. In addition, even if North Koreans are prevented from entering, a plan is necessary to ensure structural safety since most buildings in North Korea are aging and a recent natural disaster occurs frequently. In this research, we will try to present a temporary housing supply strategy and a short-term structural reinforcement plan based on analysis of the standard housing conditions in North Korea. In this research, we represent the analysis result of the existing construction level, supply status and structural performance of North Korea. When we consider the reinforcement period and social costs, a short-term reinforcement plan is recommended rather than the full reinforcement of the aged housing in North Korea. Furthermore, we examine the ways to secure the residential safety of North Koreans through a case study of domestic and overseas temporary residential facilities, until the permanent residential facilities were supplied. According to the analysis, the tent houses were used as a form of relief housing in overseas frequently. However, the tent house is difficult to apply for domestic country with clear seasons due to insulation and heating problems. Therefore, it is appropriate to develop a residential supply strategy as focusing on the temporary housing facilities in assembled or container from, in preparation for the future population inflow.

• Journal of Korean Academy of Nursing
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• v.47 no.6
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• pp.806-816
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• 2017

Purpose: As comprehensive nursing care service has gradually expanded, it has become necessary to explore the various opinions about it. The purpose of this study is to explore the large amount of text data regarding comprehensive nursing care service extracted from online news and social media by applying a semantic network analysis. Methods: The web pages of the Korean Nurses Association (KNA) News, major daily newspapers, and Twitter were crawled by searching the keyword 'comprehensive nursing care service' using Python. A morphological analysis was performed using KoNLPy. Nodes on a 'comprehensive nursing care service' cluster were selected, and frequency, edge weight, and degree centrality were calculated and visualized with Gephi for the semantic network. Results: A total of 536 news pages and 464 tweets were analyzed. In the KNA News and major daily newspapers, 'nursing workforce' and 'nursing service' were highly rated in frequency, edge weight, and degree centrality. On Twitter, the most frequent nodes were 'National Health Insurance Service' and 'comprehensive nursing care service hospital.' The nodes with the highest edge weight were 'national health insurance,' 'wards without caregiver presence,' and 'caregiving costs.' 'National Health Insurance Service' was highest in degree centrality. Conclusion: This study provides an example of how to use atypical big data for a nursing issue through semantic network analysis to explore diverse perspectives surrounding the nursing community through various media sources. Applying semantic network analysis to online big data to gather information regarding various nursing issues would help to explore opinions for formulating and implementing nursing policies.

• Journal of Information Technology and Architecture
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• v.10 no.4
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• pp.517-536
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• 2013

Warfare paradigm has been changed from PCW to NCW and the military requirement/acquisition system has been changed from bottom-up process(Weapon-Centric) to top-down process(Capability-Centric) in orde to improving the effectiveness of NCW. The concept of top down acquisition process focused on acquiring the capability based on CBP through CBA. However, implementing the concepts and embdding them into methodology will be chanllenging. So, we analyze existing examples overseas and to create new methodology which identify the our force capability through the CBA based on enimy capability. The proposed methodology can be implemented military operation area, public safety area and disaster relief area for CBP based on CBA.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2640-2644
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• 2014

With the development of technology, wireless sensor networks (WSN) are wireless networks of consisting a large number of small and low-cost sensors. Wireless sensor networks facilitate collaboration to achieve the perception of information collection, processing and transmission tasks in deployment area. They have various purposes such as military, disaster relief, medical rescue, environmental monitoring, precision farming and manufacturing industry etc. Therefore, technologies for data maintaining technologies in sensor network environment is one of essential parts of sensor networks. In this paper, we present the essential particulars about data management technology at wireless sensor network environments and propound the issues. Further, we could organize and develop a systematic approach in solving the issues.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.3
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• pp.384-388
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• 2021

Currently, whether in a domestic or international sphere, many small businesses are suffering due to COVID-19. The grim reality is that several businesses are shutting down. While the national disaster relief grant was used to contain the damages by encouraging consumer spending, it has become difficult to prevent closures of small businesses. As of September 2020, more than 20,000 stores have closed in Seoul due to the COVID-19 pandemic. There has also been an increase in the number of people with depression caused by the COVID-19 blues. This issue is not only confined to Seoul in the Republic of Korea, but is influencing all other areas affected by the pandemic. As the number of COVID-19 patients increase, the number of open stores is decreasing steadily. The analysis of the correlation coefficient of Pearson, Spearman, and Kendall suggests a negative correlation between the number of COVID-19 patients and the number of stores in business.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.19-30
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• 2021

This study evaluated the injection rate and the injection efficiency of the artificial recharge in the upper drought-prone watershed region, where the remaining water was used for injection, by using a numerical model to secure water during a drought. As a result of a numerical model under the condition of diverse injection rates per a well and hydraulic characteristics of the aquifer, the optimal injection rate per a well was estimated as 50.0 ㎥/day, and the injection efficiency was simulated as 33.2% to 81.2% of the total injection volume. As the injection time was shorter, the injection efficiency tented to increase non-linearly. As the injection rate increased, the residual storage in aquifer increased and available groundwater amount also increased, which could be advantageous for drought relief. For a more accurate assessment of injection efficiency, the model will be validated using the field injection data and optimum scenarios will enable the efficient operation of the artificial recharge system in the study area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.708-716
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• 2019

After the Sewol ferry disaster, the maritime safety supervisor system was introduced to strengthen maritime safety control for coastal vessels. If any critical defect is found in vessel facilities during periodical or occasional guidance and supervision on a vessel, a maritime safety supervisor takes an administrative measure: detention of the vessel until it has been completely corrected. The detention order is one of the most powerful regulations exercised by a maritime safety supervisor. It would not be an overstatement to say that the guidance and supervision conducted by a maritime safety supervisor is very important for the safety of a vessel and protection of the maritime environment. However, the regulatory level of each Regional Office of Oceans and Fisheries toward vessels may vary with the enforcers, and an individual's intentional act or negligence might occur during the execution process. Detention of a coastal vessel by the Regional Office of Ocean and Fisheries can easily lead to delayed navigation, and a vessel owner may suffer economic loss from suspension of a charter party. Nevertheless, the Maritime Safety Act does not prescribe filing a petition for objection to the measure of detention order by a maritime safety supervisor. To overcome this problem, therefore, the objection procedure under the Maritime Safety Act has to be reformed to reclaim a right against an inappropriate detention order measure caused by an individual's intentional act or negligence through a formal objection.

• Fire Science and Engineering
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• v.25 no.5
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• pp.119-127
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• 2011

Because of most notably the increase in vehicular traffic in Korea, as measured by highway transport usage, relief is being sought by expanding the construction of highways after 1970s'. These highways have opened up over 70 % of the mountainous areas in Korea's country side which includes the construction of tunnels. Currently there are 607 tunnels installed that are being maintained and by 2015, under the next medium-term plan, Korea will build an additional 440 tunnels. In addition, the use of 1,000m double-pole tunnels is expected to increase significantly in 256 locations. There is no doubt that these tunnels will relieve traffic congestion and aid improved communications, but halfclosed underground highway tunnels in particular are required to reduce tunnel fires caused by poor vehicle maintenance, and other factors such as speeding motorists that increase the number of vehicular accidents. Double-pole tunnels in 1,000m length over require vehicle drivers to be more cautious in terms of the continuous speed limit, judged by how devastating most of car-crash fires within these tunnels can be. In order to prevent these disasters, a full-length tunnel speed enforcement system should be considered mandatorily in legal clauses.