• Journal of Korea Water Resources Association
• /
• v.51 no.9
• /
• pp.795-802
• /
• 2018

This study investigates the hydraulic characteristics and the delta development processes in the improved-pneumatic-movable weir by considering the standing angle of the weir through laboratory experiments. The delta migration speed decreases rapidly with time. As the ratio of delta height to water depth increases, the dimensionless delta migration speed decreases at the delta point. Therefore, the water depth decreases as the delta height increases. Although the delta volume is large due to the effective height of the delta, the delta migration speed and sediment deposition decreases because of the backwater effect on the delta. On the same bed slope condition, the larger the weir height, the larger the delta volume and the ratio of delta height to delta front length is close to 1.0. The delta development could be suppressed when the weir is high. Therefore, the condition that the weir is high has the suppressing effect on the delta developments.

• International Journal of Railway
• /
• v.1 no.4
• /
• pp.143-148
• /
• 2008

This paper is the output of a collaborative European project concerning the barrier free accessibility for disabled persons to regional and long distance trains in Europe. Disabled people represent around 13% of the population in Europe. This is approximately 63 million people. The range of disabilities includes people with reduced mobility including wheel chair users, viewing and hearing impaired people and other forms of impairment. Improving accessibility aims at contributing to the provision of public transport services to all citizens in an equitable way. The purpose of the project was to analyse and to evaluate the existing solutions at selected European railways for all required modules at the entrance (doors, information and safety solutions), to derive a design concept, to develop a mock-up in meeting the needs of rail travellers with the above mentioned impairments and to test it with user groups. The project also aims at deriving components for the determination of standards. The EUPAX Design Mock-up test was performed to verify the advantages of the layout of the train segment including the different modules such as access area (including the access door, gaps between platform and train as well as boarding aid devices), entrance vestibule, information systems inside and outside the train, emergency facilities, toilet with all conveniences and the additional test arrangements regarding push buttons, steps and emergency equipment. For this purpose a questionnaire was developed for the assessment of the EUPAX segment and the additional test arrangements. With the help of this questionnaire it was possible to execute a quantitative and qualitative evaluation. During three test phases 67 experts and handicapped persons from 6 countries have evaluated the Industrial Design mock-up based on this questionnaire. The test group covered persons from North (Denmark) to the South (Italy) and from the West (Spain) to the Middle of Europe (Germany). This is especially important for the generalization (harmonisation) of the results for all European countries. According to COST 335 the information for people with reduced mobility should be clear, concise, accurate and timely. So that all information can be received from persons, they must be transferred on at least two of the three possible ways (acoustical, visual, tactile), a so called "2-sense-principle". Based on the results ergonomic specifications/ solutions for the ergonomic design of the access area, the acoustic, visual and tactile information and the emergency devices including the emergency communication system were developed, related to the benefiting passenger groups.

• Journal of Korea Water Resources Association
• /
• v.53 no.11
• /
• pp.951-960
• /
• 2020

This study investigates the adjustment processes of the rivers after weir removal through laboratory experiments. Delta upstream eroded rapidly by flow at the initial stage of the experiments and the knickpoint migrates upward. Moreover, the knickpoint moves fast upward on the condition of alternate bars. The head cutting in the bed is developed fast at the initial stage. However, the erosion speed in the bed decreases with time. The well developed alternate bars migrates with keeping their shape downstream, and the bars affect the channel downstream to adjust new environments after weir removal. Maximum scouring depth downstream and the migration speed decrease over time after removing the weir. The scouring depth in the channel without alternate bars migrates with speed. However, the depth in the channel with alternate bars migrates slow downstream. The channel with alternate bars, in turn, is adjusted well to the new equilibrium states. The maximum scouring depth migrates downstream with time, and the scouring depth and its migration speed decreases with time. The dimensionless maximum scouring depth decreases with the migration speed of dimensionless maximum scouring depth because the deeply scoured places capture the sediments from upstream and the migration speed is slow as the places are filled with them. The dimensionless maximum scouring depth is shallow as the dimensionless backfilling speed is high. The dimensionless maximum scouring depth decreases rapidly less than 5 of dimensionless backfilling speed. However, the depth decreases slow more than 5 of it.

• Korean Journal of Construction Engineering and Management
• /
• v.1 no.1 s.1
• /
• pp.87-94
• /
• 2000

Crack sealing, a routine and necessary part of pavement maintenance, is a dangerous, costly, and labor-intensive operation. Within the North America, about ${\$}200$ million is spent annually on crack sealing, with the Texas Department of Transportation (TxDOT) spending about ${\$}7$ million annually (labor alone accounts for over 50 percent of these costs). Prompted by concerns of safety and cost, the University of Texas at Austin, in cooperation with TxDOT and the Federal Highway Administration (FHWA) has developed a unique computer-guided Automated Road Maintenance Machine (ARMM) for pavement crack sealing. In 1999, successful field tests have been undertaken in 8 States around the U.S. This paper first describes significance of the automated crack sealing and technical advances in automated crack sealers including the ARMM, developed in the U.S. It then discusses the ARMM's field implementation and performance evaluation results, and improvements and modifications suggested through the technology evaluation during the field trials. Current research efforts and future work plans in its further development are also presented in this paper.

• Journal of Navigation and Port Research
• /
• v.41 no.6
• /
• pp.445-450
• /
• 2017

It is necessary to set a route to reflect the traffic flow for the safety of the traffic vessels. This ongoing analysis is needed to ensure that the vessels comply with a route. The purpose of this study is to discover the problems of the recommended route vicinity for Wando Harbor and suggest an improvement plan. We used a support vector machine based on the ship's trajectory to establish an efficient route center line. Since the vessels should navigate to the starboard side, with reference to the center line of the recommended route, the trajectories of the vessels were divided into two clusters. The support vector machine is being used in many fields such as pattern recognition, and it is effective for this binary classification. As a result of this study, about 79.5 % of the merchant eastbound ships in a 2.4 NM distance to Jangjuk Sudo did not observe the recommended route, so the risk of collision always existed. The contraflow traffic rate of the route of the eastbound ships decreased from 79.5 % to 30.9 % when the recommended route was reset about 300 meters to the north, from its present position. The support vector machine applied in this study is expected to be applicable, to effectively set the route center line because the ship trajectories can be classified into two clusters.

• Journal of Navigation and Port Research
• /
• v.41 no.6
• /
• pp.373-380
• /
• 2017

Operational errors caused by human factors, which is the major cause of marine accidents, include lack of knowledge, misunderstanding knowledge, and inadequate procedures. Recently, the type of propulsion mounted on KCG cutters has been diversified. In particular, the water jet propulsion unit, which was mainly installed in small boats, have been gradually expanded to medium and large size Coast Guard cutters, reaching 50% of the total. Axes types are divided into 2 to 4, and the bucket types are divided into Double Reverse Bucket(DRB) and Single Reverse Bucket(SRB); in these, the backward and steering control methods are completely different. Diversification of these operating systems can increase factors causing human error by the ships' operators. However, there is a lack of research on the maneuvering methods, considering the inherent active characteristics of each type of water jet. In this paper, we analyze the sideway method suitable for the condition of Coast Guard Exclusive wharf without assistance, based on the astern performance of each type. Then, a ship handling simulator was used for the experiment; they compared and verified through interviews of captains.

• Journal of Navigation and Port Research
• /
• v.37 no.2
• /
• pp.203-210
• /
• 2013

In spite of adoption of various IMO Conventions over the past, the reason why large vessel accidents related to human life and marine environment occur is that the IMO Conventions are not effectively implemented due to contravention of the conventions by flag states. In particular, the implementation of the conventions are not well being performed because some flag states having weak genuine link between them and vessels haven't set up proper personal and structural organizations in charge of maritime safety and marine environment protection. From this background, IMO Resolution A.946(23) on the voluntary IMO Member-state Audit Scheme was adopted at the 23rd Assembly in Nov. 2003 and the Scheme is expected to be executed compulsorily in 2015 through the adoption of the IMO Resolution A.1018(26) in Nov. 2009. Accordingly, this study examined outline of the IMO Member-state Audit Scheme and the Code for the Implementation of Mandatory IMO Instruments used for the audit standards of this scheme. In addition, this study reviewed the member-states' obligations and responsibilities according to the compulsory implementation of the member-state audit scheme in 2015. Based on this, this study suggested the enhancement measures for maritime education and training of maritime education institutions of the Republic of Korea to cope positively with compulsory implementation of the IMO Member-state Audit Scheme.

• International Journal of Highway Engineering
• /
• v.9 no.3
• /
• pp.1-12
• /
• 2007

Roads in Korea can be classified into four types according to their responsible authorities. For example, Motorway is constructed, managed, and operated by the Korea Highway Corporation. Ministry of Construction and Transportation is in charge of National Highway, and Province Roads are run by each province government. Urban/county Roads are run by corresponding local government. This study analyses the trends of road accidents for each road type. For this purpose, the numbers of accidents, fatalities, and injuries are compared for each road type for last 15 years. The result shows that Urban/County Roads are the most dangerous, while Motorways are the safest, when we simply compare the numbers of accidents, fatalities, and injuries. However, when we compare these numbers by dividing by total road length, National Highway becomes the most dangerous while Province Roads becomes the safest. In the case of road accidents, fatalities, and injuries per vehicle km, which is known as the most objective comparison measure, it turns out that National Highway is the most dangerous roads again. This study also developed time series models to estimate trends of fatalities for each road type. These models will be useful when we set up or evaluate targets of national road safety.

• Korean Security Journal
• /
• no.61
• /
• pp.59-85
• /
• 2019

In the reality that the boundary between the real world and the virtual world disappears with the 4th Industrial Revolution, cyber crimes that occur beyond time and space have clear limitations in fulfilling their duties only with the police force of government organizations established under the real law system. The research method of this thesis is based on the literature research and the experience of security work. The purpose of this paper is to establish a social system where collective intelligence of each social field can participate voluntarily to respond to cyber crimes occurring beyond the time and space before the law and institutionalization. In addition, the social system in which collective intelligence in each social sector can participate voluntarily was established to define crime types in cyberspace in real time and to prevent crimes defined by the people themselves and the counter-measures had been proposed in order to form social consensus. First, it is necessary to establish a collective intelligent network-type cyberpolice volunteer system. The organization consists of professors of security and security related departments at universities nationwide, retired public officials from the National Intelligence Service, the National Police Agency, and the National Emergency Management Agency, security companies and the organizations, civilian investigators, security & guard, firefighting, police, transportation, intelligence, security, national security, and research experts. Second, private sector regulation should be established newly under the Security Business Act. Third, the safety guard of the collective intelligent cyberpolice volunteer system for the stability of the people's lives should strengthen volunteer work. Fourth, research lessons and legal countermeasures against cybercrime in advanced countries should be introduced. Fifth, the Act on the Protection of Personal Information, the Act on Promotion of Information and Communication Network Utilization and Information Protection, the Act on the Utilization and Protection of Credit Information, and the Special Act on the Materials and Parts Industry should be amended. Sixth, police officers should develop cybercrime awareness skills for proactive prevention activities.

• Journal of Korea Water Resources Association
• /
• v.53 no.8
• /
• pp.583-595
• /
• 2020

In this study, using the RCP scenario for Hyoja Drainage subbasin of Cheonggyecheon, we analyzed the change with the Historical and Future rainfall calculated from five GCMs models. As a result of analyzing the average rainfall by each GCMs model, the future rainfall increased by 35.30 to 208.65 mm from the historical rainfall. Future rainfall increased 1.73~16.84% than historical rainfall. In addition, the applicability of LID element technologies such as porous pavement, infiltration trench and green roof was analyzed using the SWMM model. And the applied weight and runoff for each LID element technology are analyzed. As a result of the analysis, although there was a difference for each GCMs model, the runoff increased by 2.58 to 28.78%. However, when single porous pavement and Infiltration trench were applied, Future rainfall decreased by 3.48% and 2.74%, 8.04% and 7.16% in INM-CM4 and MRI-CGCM3 models, respectively. Also, when the two types of LID element technologies were combined, the rainfall decreased by 2.74% and 2.89%, 7.16% and 7.31%, respectively. This is less than or similar to the historical rainfall runoff. As a result of applying the LID elemental technology, it was found that applying a green roof area of about 1/3 of the urban area is the most effective to secure the lag time of runoff. Moreover, when applying the LID method to the old downtown area, it is desirable to consider the priority order in the order of economic cost, maintenance, and cityscape.