• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.783-788
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• 2002

Adaptive Cyclic Packet Dropping algorithm (ACPD), and Non-adaptive Cyclic Packet Dropping algorithm (NCPD) are applying stricter drop precedence than that of RIO algorithm. Especially, the ACPD algorithm drops adaptively packets for the congestion control, as predicting traffic pattern between each cycle. Therefore the ACPD algorithm makes up for the drawback of RIO algorithm and minimizes the wastes of the bandwidth being capable of predicting in the NCPD algorithm. And we executed a simulation and analyzed the throughput and packet drop rate based on Sending Priority changing dynamically depending on network traffic. In this algorithm, applying strict drop precedence policy, we get better performance on priority levels. The results show that the proposed algorithms may provide more efficient and stricter drop precedence policy as compared to RIO independent of traffic load. The ACPD algorithm can provide better performance on priority levels and keep stricter drop policy than RIO and the NCPD algorithm.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.46-53
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• 1999

As of July 1999, i,185 lomocotives(excluding metropolitan area electric locomotives) are in Korean National Railroad(KNR). With this limited number of resources assigning locomotives to each trains of timetable is very important in the entire railway management point of view because schedule can be regarded as goods in transportation industry. On a simple rail network, it is rather easier to assign proper locomotives to trains with the experience of operating experts and get optimal assignment solution. However, as the network is getting bigger and complicated, the number of trains and corresponding locomotives will be dramatically increased to rover all the demands required to service all of the trains in timetable. There will be also numerous operational constraints to be considered. Assigning proper locomotives to trains and building optimal cyclic rotations of locomotive routings will result in increasing efficiency of schedule and giving a guarantee of more profit. The purpose of this study is two fold: (1) we consider a planning-level locomotive scheduling problem with the objective of minimizing the wasting cost under various practical constraints and (2) development of implementation prototype program of its assigning result. Not like other countries, i.e. Canada, Sweden, Korean railroad operates on n daily schedule basis. The objective is to find optimal assignment of locomotives of different types to each trains, which minimize the wasting cost. This problem is defined on a planning stage and therefore, does not consider operational constraints such as maintenance and emergency cases. Due to the large scale of the problem size and complexity, we approach with heuristic methods and column generation to find optimal solution. The locomotive scheduling prototype consists of several modules including database, optimization engine and diagram generator. The optimization engine solves MIP model and provides an optimal locomotive schedule using specified optimization algorithms. A cyclic locomotive route diagram can be generated using this optimal schedule through the diagram generator.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.325-333
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• 2010

In this study, new moment-resisting precast concrete beam-column joint made up of hybrid steel concrete was developed and tested. This beam-column joint is proposed for use in moderate seismic regions. It has square hollow tubular section in concrete column and connecting plate in precast U-beam. The steel elements in column and beam members were connected using bolt. Furthermore, in order to prevent the premature failure of concrete in hybrid steel-concrete connection, ECC(engineered cementitious composite) was used. An experimental study was carried out investigating the joint behavior subjected to reversed cyclic loading and constant axial compressive load. Two precast beam-column joint specimens and monolithic reinforced concrete joint specimen were tested. The variables for interior joints were cast-in-situ concrete area and transverse reinforcement within the joint. Tests were carried out under displacement controlled reverse cyclic load with a constant axial load. Joint performance is evaluated on the basis of connection strength, stiffness, energy dissipation, and displacement capacity. The test results showed that significant differences in structural behavior between the two types of connection because of different bonding characteristics between steel and concrete; steel and ECC. The proposed joint detail can induce to move the plastic hinge out of the ECC and steel plate. And proposed precast connection showed better performance than the monolithic connection by providing sufficient moment-resisting behavior suitable for applications in moderate seismic regions.

• Journal of The Korea Institute of Healthcare Architecture
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• v.22 no.4
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• pp.7-17
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• 2016

Purpose: As our population ages and becomes an elderly society the number of elderly care hospitals is rapidly increasing. Because physical functions and spatial perception in the elderly decrease with age, these hospitals require more systematic and intelligent space designs. The design of these spaces are even more complex because they must accommodate medical programs to treat various different diseases and ailments and also because there are many first time patients and irregular short term patients that seek out outpatient treatment services. Also by analyzing the spatial configuration systems and systematic relationships between each of the functional spaces of the outpatient treatment service departments for hospitals specialized in care for the elderly by focusing on the hallway and corridor systems of these hospitals, the according characteristics and trends were examined. Methods: Based on preceding research, the types of hallway and corridor systems of these hospitals were categorized into five types, including gallery corridors, middle corridors, hall-type, mixed type and cyclic type corridors, and into six types according to function including by medical diagnosis, patient registration, examination, administration and convenience and shared common space to derive any interconnecting relationships between the corridor systems. Also by comprehensively examining the types and combined utilization of the corridor types and the integration and the intelligibility of the space syntax, any trends within the corridor system were derived. The elderly care hospitals examined in this research study were twelve hospitals that opened after the year 2000 in Korea with more that 150 sick beds with areas larger than $1000m^2$ and with all outpatient medical service related rooms located entirely on a single floor of the hospital. Results: The following results could be confirmed based on this research study. 1) The spaces where medical diagnosis and examination occurred were adjacent, and the movement lines for first time patients and re-visiting patients were taken into consideration by separating the treatment space. 2) This research study confirmed that the larger the size of the hospital was, there were more detailed categorizations of treatment services and that there was a tendency for treatment areas to be separated and independent from examination areas. 3) There was a tendency for integration and intelligibility to decrease the more complex and diverse the combination of hall types designed into the corridor systems of these hospitals was. cyclic type corridors dramatically decreased the intelligibility of the corridor systems of these hospitals. 4) The priority rank of these spaces were confirmed to be highest in the order of registration, diagnosis, examination, treatment, administration and shared common spaces. However it was confirmed for the local integration that the diagnosis scope had the highest priority rank. Implications: There were exceptional cases confirmed where the number of unit spaces did not have an absolute effect on integration and intelligibility. These results can be interpreted to mean that this can be overcome through efficient architectural planning.

• Journal of The Korean Association For Science Education
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• v.34 no.2
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• pp.135-146
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• 2014

The purpose of this study is to explore evaluation criteria that pre-service elementary teachers employ as they evaluate and select models to explain electric circuits. Thirty junior students in a university of education have participated in the study as a part of the science education course in which they were enrolled. The lessons for the participants have been organized as a cyclic sequence of different modeling pedagogies including the expressive, experimental, and evaluative modeling. The pre-service teachers have been given five electric circuits in order and asked to create models and further develop them through peer discussion. Their modeling activities have been video- or audio-recorded, and the recordings and their transcripts have been analyzed using a framework of model evaluation criteria. It reveals that the types and frequencies of evaluation criteria used are different between situations of model development and model selection. While empirical and theoretical criteria have been used dominantly in both situations, more various criteria have been employed in the situation where the pre-service teachers selected one model among alternatives. Implications for science education and science education research have been suggested.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.1
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• pp.11-23
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• 2007

In this paper, we design and implement a framework based on Web Services for effective management of the profiles that were proposed to provide a user with personalized service. The profiles must be constituted the related information of the user and could be exchanged according to cyclic.acyclic or event among user's device, profile repository and service server for providing the user with personalized service. The profiles also must be supplied the services providers that need to the profiles for the personalized service. The profile framework is necessary to provide the functions like this for managing effectively of the personalized service. The proposed framework used the Web Services for exchanging and providing the profile regardless the various devices and platform. The framework also was applied the metadata constitute method and dynamic constitute method for managing effectively of the profile. The result of experiment using proposed framework was effective process and management of the profile and could exchange the profile with regardless of platform and device. The implemented system using the proposed framework was foundation of providing the personalized services with a user by through a effective management function of the profile.

• Advances in concrete construction
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• v.9 no.3
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• pp.313-326
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• 2020

Glass fiber-reinforced polymer (GFRP) bars have been introduced as an effective alternative for the conventional steel reinforcement in concrete structures to mitigate the costly consequences of steel corrosion. However, despite the superior performance of these composite materials in terms of corrosion, the effect of replacing steel reinforcement with GFRP on the seismic performance of concrete structures is not fully covered yet. To address some of the key parameters in the seismic behavior of GFRP-reinforced concrete (RC) structures, two full-scale beam-column joints reinforced with GFRP bars and stirrups were constructed and tested under two phases of loading, each simulating a severe ground motion. The objective was to investigate the effect of damage due to earthquakes on the service and ultimate behavior of GFRP-RC moment-resisting frames. The main parameters under investigation were geometrical configuration (interior or exterior beam-column joint) and joint shear stress. The performance of the specimens was measured in terms of lateral load-drift response, energy dissipation, mode of failure and stress distribution. Moreover, the effect of concrete damage due to earthquake loading on the performance of beam-column joints under service loading was investigated and a modified damage index was proposed to quantify the magnitude of damage in GFRP-RC beam-column joints under dynamic loading. Test results indicated that the geometrical configuration significantly affects the level of concrete damage and energy dissipation. Moreover, the level of residual damage in GFRP-RC beam-column joints after undergoing lateral displacements was related to reinforcement ratio of the main beams.

• Korean Journal of Veterinary Service
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• v.21 no.1
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• pp.57-66
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• 1998

To establish the differential diagnosis and treatment method in bovine ovarian cysts, specially ovarian cysts with corpus luteum, serum progesterone concentration and ulrasonography for measuring the cyclic area, thickness of cystic wall and echogenicity of corpus luteum were investigated in cystic ovaries from slaughtered cows. The incidence rates of ovarian cysts were follicular cyst 69.2% and luteal cyst 30.8%. The incidence rates of 8 various types of ovarian cysts were as follows; 2Ba 32.3%, 2Aa 25.8% and 2Bb 14.5%, respectively. The thickness of cystic wall were 2Bb 3.93mm, 2Ab 3.70mm and 1Aa 1.93mm and the serum progesterone concentrations were above 1.0ng/$m\ell$ in 2Ab, 2Bb and IAa, respectively. The cystic area of ovarian cysts with corpus luteum was 288.30mm2, but ovarian cysts without corpus luteum 542.30$\textrm{mm}^2$, and the thickness of cystic wall 2.12mm and 2.40mm, respectively. The serum progesterone concentration was 1.91ng/$m\ell$ in ovarian cysts with corpus luteum and 1.20ng/$m\ell$ ovarian cysts without corpus luteum. There was not the correlations between thickness of cystic wall and serum progesterone concentration in ovarian cysts with corpus luteum, whereas, was the correlations in ovarian cysts without corpus. These results indicated that PGF2$\alpha$ analogues can be choice for treating the ovarian cysts with corpus luteum because serum progesterone concentrations were above 1.0ng/$m\ell$ in ovarian cysts with corpus luteum. In conclusion, it is suggest that ultrasonography is useful diagnostic tool for diagnosing and choicing of treatment remedy in cystic ovaries of bovine.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.4
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• pp.23-32
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• 1982

In order to obtain the necessary data for the safety maintenance, repair, and reinforcement of steel structures, experiment was carried out to examine the mechanical capacity and toughness variation for steel with service history and without. In this paper, hardening and embrittlement by fatigue accumulation, and the decrease of toughness was examined and weld that was commonly used as the connection method of steel structure was also examined. It was found that hardening and embrittlement have more effect on the decrease of toughness than the increase of strength. Such a tendency was also similary state in case of weld. And it was found that, in the weld of steel with service history and without, embrittlement was observed at normal temperature.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.4
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• pp.53-60
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• 2003

Large sized marine structures are used under corrosion environment of seawater and applied by severe service loading such as an ocean current, a billow and a tempest. Marine structures are usually constructed by lots of thick wall steel pipes joining welded joints. The thickness of such as steel pipes is usually more than 40mm. The such as steels are called "Thermo-Mechanical Control Process steel (TMCP steel)" strengthened by a heat treatment in process of steel manufactures. The failure, especially crack initiation, of marine structures was starting at weld joints under service condition. Then they should be designed by basis of the fatigue strength under seawater corrosion environment of weld joints. To clarity the fatigue crack initiation behavior is important more than to clarify the crack propagation behavior on the strength design of marine structures, because it is very difficult to find out the crack initiation and propagation phenomena and then even if it will be able to find out, it is considered that the refit of the damaged parts of welded joints have a technical difficulty under the sea. Therefore, it is most important to clarify the corrosion fatigue crack initiation behavior under the seawater condition. But, there is one big difficulty to make a test for thick plate specimen, for example thicker than 40mm. Because, it is need large capacity loading apparatus to test such as thick plate specimen. In this research, the new configuration specimen for fatigue crack initiation tests was proposed. Using this new specimen, it is easy to carry out the fatigue clack initiation tests with relatively low cyclic loading and to observe a fatigue crack initiation behavior.