• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.5
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• pp.566-582
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• 2018

A moored barge alongside quay can be influenced by a nearby passing ship and its ship-generated waves. In this study, a time-domain numerical method based on a three-dimensional potential flow solver is developed to investigate the passing ship problem with a moored barge alongside quay. Potential flows around the passing ship and the moored barge alongside a quay is directly solved by using a classical finite element method. Total computational meshes including a passing ship, a moored barge and a quay is updated at each step with an efficient re-mesh algorithm. To validate the developed numerical method, a conventional ship wave problem and a passing ship problem on the open sea has been solved and the solutions are compared with the existing data. Then, a series of numerical computations were carried out to investigate the passing ship effect on a moored barge alongside quay. The characteristics of the passing ship effects are studied with varying the simulation parameters such as passing ship speed, separation distance, wall distances and waves. Focus is made on hydrodynamic forces due to the passing ship effect and its ship waves.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.111-113
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• 2006

FOUNDATION fieldbus provides scheduling and token-passing services for cyclic and sporadic data respectively. In this paper, we evaluate the delay performance of token-passing mechanism in FOUNDATION fieldbus network system using an experimental model. This paper introduces a method of developing an experimental model which consists of 10 nodes of FOUNDATION fieldbus communication device. Using the experimental model, we evaluate the delay performance of time-critical and time-available data with respect to change of TTRT parameter.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.181-184
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• 2003

Recently, the fieldbus becomes an indispensable component for many automated systems. In the fieldbus system, realtime data containing sensor values and control commands has a tendency to rapidly lose its value as time elapses after its creation. In order to deliver these data in time, the fieldbus network should be designed to have short delay compared to the maximum allowable delay. Because the communication delay is affected by performance parameters such as target rotation timer of token passing protocol, it is necessary to select proper parameter settings to satisfy the real-time requirement for communication delay. This paper presents the timer selection method for Profibus token passing networks using genetic algorithm (GA) to meet the delay requirements.

• Journal of English Language & Literature
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• v.53 no.2
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• pp.307-333
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• 2007

When W. E. B. Du Bois says that "the problem of the twentieth century is the problem of the color line," such a statement clearly recognizes the significance of the issue of racial identity, a cultural phenomenon called 'passing.' Both Johnson in The Autobiography of an Ex-Colored Man and Larsen in Passing confront this issue. Both novels, using the metaphor of passing, not only trace the racial anxiety and race politics of the time but also expose the unstable landscape of the established social and cultural boundaries of racial identity. Mapping out multiple meanings and various dimensions of passing, this paper argues how Johnson's and Larsen's narratives display the ambivalence of color line while they at the same time complicate, problematize, and destabilize the mainstream racial boundaries and differences. It furthers to delineate how the two writers, with difference, deal with the problem of passing, the significance of racial identity, and black middle class values along with its intraracial differences. Rather than draw a clear definition of and a definitive closure on passing narrative, this paper focuses on its complexities and undecidability, challenging every dimension of its established significations. It also explores the complex dynamic between passing act and individual identity, for passing here is not just a racially signified term but extends its significance to the other factors of identity, such as class and even sexuality. Johnson and Larsen open up a site for a newly emergent, modern racial identity for black middle class in the twentieth century American urban spaces. Both writers, illuminating the subversive and slippery nature of language in their passing narrative, clearly herald new, different forms of Afro-American writings and themes for the different century they face.

• Journal of the Korean Society of Systems Engineering
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• v.19 no.1
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• pp.1-13
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• 2023

Transportation of goods by rail in border areas requires considerable time, money, and human resources. Therefore, in this study, a blockchain-based non-stop passing system is proposed to solve this problem. In this study, each transit station and train are designated as one network node, and the corresponding node participates in the blockchain network to record and verify data. In the process, we will design a blockchain network using Docker and design a network interface. Without changing the data and information generated in the existing legacy clearance system, it is possible to configure a blockchain network to ensure the integrity and reliability of the data and to minimize the consumption of time and human resources. The railroad non-stop passing system aims to change the existing legacy system to a blockchain-based non-stop passing system.

• Journal of Internet Computing and Services
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• v.9 no.5
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• pp.185-193
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• 2008

An MTBF(mean time between failures) of large scale parallel systems is known to be only an order of several hours, and large computations sometimes result in a waste of huge amount of CPU time, However. the MPI(Message Passing Interface), a de facto standard for message passing parallel programming, suggests no possibility to handle such a problem. In this paper, we propose an application-level fault tolerant computation system, purely on the basis of the current MPI standard without using any non-standard fault tolerant MPI library, that can be used for general scientific synchronous parallel computation.

• Journal of Korean Society of Transportation
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• v.24 no.5 s.91
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• pp.7-18
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• 2006

Data for travel information Provision are regularly aggregated to Provide travel time information in a reliable and convenient manner and to manage traffic data and information efficiently. In most of practices in Korea, the GPS based travel time data are mainly aggregated every 5 minutes As a result, some probes can't pass by a link within aggregation interval and thereby create uncompleted link passing data. But these data are mostly generated during the congested times and therefore a method that uses such uncompleted link passing data are required. This study estimated queue dissipation length, green time and cycle that use GPS spot speed and developed a link travel time estimation method using such uncompleted link passing data. It also presents method and the overall process of using such data to estimate link travel time in a more accurate manner. As a result, MAPE 1.98% and MAE 4.75 sec of link travel time accuracy improvement has been reported, which is not much different from the real link travel time. The method Proposed here would be an alternative to increase the amount of GPS probe data, especially in congested urban arterial case.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.135-144
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• 2013

PURPOSES : The purpose of this paper is to develop a methodology to estimate level of service of arterial including Exclusive Median Bus Lanes. METHODS : On 6 Exclusive Median Bus Lanes routes in Seoul, bus travel time and number of bus-stop per km were investigated. Also whether or not passing lane exists at bus-stop was checked. Based on the data from sites, bus travel time was estimated according to length of segment, number of bus-stop per km and whether or not passing lane exists at bus-stop. RESULTS : A bus travel time table was developed according to length of segment, number of bus-stop per km and whether or not passing lane exists at bus-stop. After bus travel speed and passenger car travel speed is estimated based on each travel time table and length of segment, two speeds are combined with weighted average speed using traffic volume of each lane group. Then weighted average speed is a measure of effectiveness of arterial including Exclusive Median Bus Lanes. CONCLUSIONS : It can be concluded that the proposed methodology can estimate level of service of arterial including Exclusive Median Bus Lanes considering the operation characteristics of Exclusive Median Bus Lanes.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.37-42
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• 1992

The main purpose of the paper is to derive asymptotic formulae for performance characteristics(throughput, delay) of large-scale token-passing network with buffered stations and to optimize the buffer capacity with respect to the probability of data generation. We consider two versions of token-passing network: uniform and nonuniform token-passing time interval. All results obtained are supported by simulations.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.91-98
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• 2009

For maintaining railroad, accumulated passing tonnage is a determinant factor of appropriate rail replacement time. Recently, Seoul Metro's rail maintaining system and technology is being improved from previous years, which increasing a standard of rail replacement. Thus, this brings importance of estimating and managing for accumulated passing tonnage. In case of light weighted train such as subway, current method of calculating accumulated passing tonnage has defaults of misrepresenting accumulated passing tonnage data. Because current method is based on the weight of passengers and train., and operation data. In addition, currently there is no mechanical and electronic system that could represent and support the accurate data between heavy and non-heavy traffic area, and accumulated passing tonnage is calculated inaccurately by estimating average value each line. The current method of calculating accumulated passing tonnage misleads to unpredictable data that represent inappropriate rail replacement period, which leads to under or over analyzed replacement period. If accumulated passing tonnage is over estimated, rail replacement leads to waste of budget. Hence, it is necessary to construct reliable actual measurement system to manage rail's life safely and efficiently, and in this study the accumulated passing tonnage measurement device is installed with using rail pad of optical fiber sensors and its effect is analyzed.