• Advances in concrete construction
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• v.16 no.3
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• pp.155-167
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• 2023

The penetrated chloride in concrete has different behavior with mix proportions and local exposure conditions, even in the same environments, so that it is very important to quantify surface chloride contents for durability design. As well known, the surface chloride content which is a key parameter like external loading in structural safety design increases with exposure period. In this study, concrete samples containing OPC (Ordinary Portland Cement), GGBFS (Ground Granulated Blast Furnace Slag), and FA (Fly Ash) had been exposed to submerged, tidal, and splash area for 5 years, then the surface chloride contents changing with exposure period were evaluated. The surface chloride contents were obtained from the chloride profile based on the Fick's 2nd Law, and the regression analysis for them was performed with exponential and square root function. After exposure period of 5 years in submerged and tidal area conditions, the surface chloride content of OPC concrete increased to 6.4 kg/m³ - 7.3 kg/m³, and the surface chloride content of GGBFS concrete was evaluated as 7.3 kg/m³ - 11.5 kg/m³. In the higher replacement ratio of GGBFS, the higher surface chloride contents were evaluated. The surface chloride content in FA concrete showed a range of 6.7 kg/m³ to 9.9 kg/m³, which was the intermediate level of OPC and GGBFS concrete. In the case of splash area, the surface chloride contents in all specimens were from 0.59 kg/m³ to 0.75 kg/m³, which was the lowest of all exposure conditions. Experimental constants available for durability design of chloride ingress were derived through regression analysis over exposure period. In the concrete with GGBFS replacement ratio of 50%, the increase rate of surface chloride contents decreased rapidly as the water to binder ratio increased.

• Steel and Composite Structures
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• v.51 no.4
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• pp.351-361
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• 2024

Accurate measurement of K_IC values for gas pipeline steels is important for assessing pipe safety using failure assessment diagrams. As direct measurement of K_IC was impossible for the API X70 pipeline steel, multi-specimen fracture tests were conducted to measure J_IC using three-point bend geometry. The J values were calculated from load-displacement (F-δ) plots, and the associated crack extensions were measured from the fracture surface of test specimens. Valid data points were found for the constructed J-Δa plot resulting in J_IC=356kN/m. More data points were added analytically to the J-Δa plot to increase the number of data points without performing additional experiments for different J-Δa zones where test data was unavailable. Consequently, displacement (δ) and crack-growth (Δa) from multi-specimen tests (with small displacements) were used simultaneously, resulting in the variation of Δa-δ (crack growth law) and δ-Δa obtained for this steel. For new Δa values, corresponding δ values were first calculated from δ-Δa. Then, corresponding J values for the obtained δ values were calculated from the area under the F-δ record of a full-fractured specimen (with large displacement). Given Δa and J values for new data points, the developed J-Δa plot with extra data points yielded a satisfactory estimation of J_IC=345kN/m with only a -3.1% error. This is promising and showed that the developed technique could ease the estimation of J_IC significantly and reduce the time and cost of expensive extra fracture toughness tests.

• Hip & pelvis
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• v.36 no.2
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• pp.108-119
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• 2024

Purpose: The incidence of deep vein thrombosis (DVT) following total hip arthroplasty (THA) without chemoprophylaxis could be as high as 50% in Caucasians. However, according to several subsequent studies, the incidence of venous thromboembolic events (VTE) in Asians was much lower. The routine use of chemoprophylaxis, which could potentially cause increased bleeding, infection, and wound complications, has been questioned in low-incidence populations. The objective of this study is to determine the incidence of VTE after primary THA without chemoprophylaxis in an Asian population using a fast-track rehabilitation protocol and to verify the safety profile for use of 'mechanical prophylaxis alone' in patients with standard risk of VTE. Materials and Methods: This is a retrospective cohort study of 542 Hong Kong Chinese patients who underwent primary THA without chemoprophylaxis. All patients received intermittent pneumatic compression and graduated compression stockings as mechanical prophylaxis. Multimodal pain management was applied in order to facilitate early mobilisation. Routine duplex ultrasonography was performed between the fourth and seventh postoperative day for detection of proximal DVT. Results: All patients were Chinese (mean age, 63.0±11.9 years). Six patients developed proximal DVT (incidence rate, 1.1%). None of the patients had symptomatic or fatal pulmonary embolism. Conclusion: The incidence of VTE after primary THA without chemical prophylaxis can be low in Asian populations when following a fast-track rehabilitation protocol. Mechanical prophylaxis alone can be regarded as a reasonably safe practice in terms of a balanced benefit-to-risk ratio for Asian patients with standard risk of VTE.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.41-53
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• 2010

Traffic safety assessment is often accomplished by analyzing the number of crashes occurring in some geographic space over certain specific time duration. In this paper, we introduce a procedure that can efficiently analyze spatial and temporal changes in traffic crashes before-and-after implementation of a certain traffic controlling measure. For the analysis, crash frequency data before-and-after closing a major highway around St. Louis in Missouri was collected through Transportation Management System(TMS) database that is maintained by Missouri Department of Transportation (MoDOT). In order to identify any spatial and temporal pattern in crashes, each crash is pinpointed on a map using the dynamic segmentation in GIS. Then, the identified pattern is statistically confirmed using an analysis of variance table. The advantage of this approach is to easily assess spatial and temporal trend of crashes that are not readily attainable otherwise. The results from this study can possibly be applied in enhancing the highway safety assessment procedure. This paper also makes several suggestions for future development of a comprehensive transportation data system in Korea which is similar to MoDOT's TMS database.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.1-12
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• 2011

There has been the increasing concern with the safety of seven major urban infrastructure such as road, electricity, water supply, sewerage and so on due to urban expansion and new town development. However, high technology development for the common duct which can be an alternative for the safety issue has not been completed due to the law of the national security area. Existing management method of the common duct by people could not respond to the urgent accidents adequately and immediately since it is impossible for us to get access to that in case of fire or gas leak. This study suggests to the method of installing monitoring devices and processing CCTV images with a water supply in a TestLab(a variety of the USN(Ubiquitous Sensor Network) equipment was tested in the TestLab in KICT). The suggested management method of common duct facilities make it possible to do real-time monitoring and prompt access and response to an accident inside the common duct.

• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.64-71
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• 2016

According to the urban gas business law, electrical corrosion prevention measures shall be installed to the buried gas pipelines and the pipe-to-soil potentials should be measured at the test box at least once a year. Most of the test boxes installed in urban area are usually located on the road where the vehicle travels, therefore, it is difficult to measure the CP potentials at the test boxes. That is, we need traffic control when carrying out the measurement of the CP potentials on daytime when the traffic is heavy, or we have to measure the potentials in the late night when the traffic is light. To solve these difficulties, we have studied remotely CP potential measuring method by using the patrol car. We have installed solid reference electrodes and data loggers under the test boxes on the site and received the CP potentials from the data loggers when the vehicle moves. It was difficult to send and receive the data because the data logger was located under the ground. We have applied 3 different method including 2 antenna systems to achieve best effective way in receiving the data. We have found the remote CP measuring method by using a car can save more 20 times of measuring time than conventional measuring methods.

• Journal of Korean Society of Transportation
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• v.23 no.6 s.84
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• pp.41-53
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• 2005

The effective utilization of an airport is considerably influenced by natural features and man-made structures inside and outside its boundary. These obstacles affect the airspace available for approaches and departures and the weather minima which dictates the necessary weather conditions for aircraft to be allowed to take-off or land. Certain areas of the airspace near airports must be regarded as the integral parts of the airport system. The availability of the required airspace is as important as are the runway and their associated strips to the safe and efficient use of the airport. For these reasons, ICAO and the member states have established the standards regarding the obstacle limitation surfaces and regulated the construction of the man-made structures in and beyond the surfaces. Existing objects that extend above a obstacle limitation surfaces should as for as practicable be removed except when, in the opinion of the appropriate authority, an objects is shielded an existing immovable objects, or after aeronautical study it is determined that the object would not adversely affect the safety or significantly affect the regularity of operations of airplanes. However, Korea's aviation law does not specified the outer horizontal surface in the obstacle limitation surfaces, while ICAO and most member states do. The absence of the outer horizontal surface regulation has created legal disputes between regulating agencies and private parties. The case study in this paper found that a skyscraper planned beyond Korea's obstacle limitation surfaces does affect the flight safety and the efficient use of an airport. Therefore, in areas beyond the obstacle limitation surfaces. those objects which extend to a height of 150m or more above ground elevation should be regarded as obstacle, unless a special aeronautical study indicates that they do not constitute a hazard to airplanes. We proposed low alternative regulatory schemes for resolving the issues raised in this paper, and we recommended to adopt ICAO's standards and recommended practices.

• Korean Journal of Occupational Health Nursing
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• v.6 no.2
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• pp.156-167
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• 1997

In Korea, based on the Revised Law of Occupational Safety and Health a new entity of institution was set up in 1990 to provide occupational health services to SSE in which three sorts of personnel as a team have to be involved. These institutions, in charge of scores to hundreds of workplace area-wide, have been providing occupational health services without payment from employers or employees, and government reimburses through the Occupational Injury Prevention Insurance since 1993. As a service provider, a team is composed of doctors, nurses and industrial hygienists. Undergraduate and postgraduate educations for the SSE occupational health are not specified and the question on the performance of the personnel has been raised. This study was designed to analyze the facilitating factors of and barriers to the performance and its improvement of these personnel. In 1997, the survey was conducted with all 58 institutions. Structured questionnaires were mailed to 200 personnel who were providing the occupational health service for SSE. The response rate was 51.7% for doctors, 58.6% for nurses, and 60.3% for industrial hygienist, respectively. Results are as follows : 1) There is a guideline for occupational service mandated by the government. Under the guideline, the minimum frequency of visiting workplace is assured with six times of doctors, 17 times for nurse and industrial hygienist in a year. There are one doctor for every 200 factories, one nurse and one hygienist for every 100 factories. 2) All respondents have basic qualification for occupational health service. About 16.7%. of doctors are certified in industrial medicine or preventive medicine, and 64.7% of industrial hygienists had first grade certification. Totally 66.7% of personnel have been involved in occupational health for more than one year. 3) As a support system for the performance improvement, 66.3% respond that they have been provided with educational materials, advice related to industrial environment and guidance of MSDS from Korea Industrial Safety Corporation. Most respondents indicate the lack of concern of employers and employees as a main barrier to the improvement of the service. Also they are in the need of the training opportunity more focused on SSE. The Governments policy for SSE is a principal facilitating factor. Training program focused on SSE situation, manpower, technical support, etc. are areas to be improved to have a better occupational health service for SSE in Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6D
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• pp.755-764
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• 2011

At the present, planning and installation of parking space sections and lane width are implemented in accordance with the installation standard and parking lot structure by the enforcement regulations of the Parking Act. While large and RV (Recreational Vehicle) vehicles have increased in number recently, parking is complex with improper installation standards. It causes serious problems, including vehicle vandalism, increased civil complaints, travel inconveniences for parking lot users, management and maintenance issues for parking lots, and so forth. The study, therefore, determined that the practical and appropriate realignment of parking unit adjustment and lane width regulations are essential. The study conducted prior review on domestic parking sections and change cases of composition by vehicle types, including the component ratio of domestic and foreign vehicles, width of vehicle by types in order to examine the parking problems that account for a increasing social issues, and provided parking plan methods by types of vehicle, as well as reform and reaction plans for parking unit adjustment and lane width considering security and smooth traffic flow. After comparing and analyzing between estimated installation of parking space and lane width and internal and external cases, the study suggests the improvement that considers expenses and convenience of a driver. Also, it shows installation of parking space that considers traffic safety, improvement of lane width, and parking way depends on vehicle types. By providing estimation for parking planning and parking planning methods that secure safe and smooth traffic flow within a parking lot, the study will contribute to the development of improved alternatives for cost-effective traffic safety and set-up structure, including installation standards of parking lots.

• Korean Security Journal
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• no.36
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• pp.29-55
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• 2013

In modern society, citizen's expectation about policing levels have been rising over time and it limited resources of the police to deal with the security services are insufficient. Until now, the state monopoly of the police activity was changing to subject of a variety in cooperation with public security system. The citizens considers community not the destination to police enforce the law but space for effective policing partners. Japanese police focus on cooperation oriented policing to strengthen the police and local residents with crime prevention for a long time. Also, the community through a variety of problem-solving policing activities to identify problems such as anxiety and anguish of the people. The legal basis for cooperative policing activity is that Nagaoka city crime prevention regulation in 1979. In recent years, Tokyo local government legislated the safe town development regulations(東京都安全 安心まちづくり條例) and set up the hot-spot area to promote the safety of public facilities. Cooperative policing not police intervention for crime prevention but national policy for the city reclamation in Japan. Police as well as the Ministry of Land and Transport, Ministry of Justice, Ministry of Education, Prime Minister and all government departments thread safe city, crime prevention, and has been working to make the safe city. Japan's cooperative policing is a system that receives the most attention and greater implications.