• Journal of the Korean Geographical Society
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• v.39 no.6 s.105
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• pp.863-872
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• 2004

The coastal alluvial plain, sand dune, tidal nat might be the most prominent coastal landscape in western coast of Korea. The purpose of this paper is to examine the irrigation and drainage systems of the alluvial plain in the tidal coast. This study is concerned on the geomorphological and cultural landscapes of the alluvial plain in the western coast of the South Jeolla Province. The alluvial deposits have developed mainly by the actions of tidal currents, rather than transporting sediments by stream. The transformation of plain has been affected by human agency since 1920's. Dwellers have constructed the reservoir, banks, dammed pools, lock gates, and tide-dykes for the reclamation, irrigation, and drainage on the alluvial plain, coastal sanddune, and tidal flats.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.661-663
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• 2016

Corruption occurs in the process of processing image signal and the corruption changes the pixel value within the image to damage the original information. AWGN(additive white Gaussian noise) is a representative example. For filters to remove AWGN, there are filters such as MF(mean filter), WF(wiener filter), and AWMF(adaptive weighted mean filter). However images processed through standard previous filters lock preservation characteristics in edge areas. Therefore, threshold value is applied for processing on the standard deviation of the local mask in this study and if the standard deviation is smaller than the threshold value, it is not filtered and if the value is bigger than the threshold value, the study suggested an algorithm that processes using weighted value utilizing standard deviation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.2
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• pp.137-145
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• 1986

The contention resolution algorithm with the limited packet delay time as well stable distribution as the packet delay time is proposed and implementes for improving the mean packet delay time in the network employing CSMA/CD as the access method. The implementation of node controller is based on IEEE 802.2 standard logical link control(LLC) and IEEE 802.3 standard medium access control(MAC). Some portion of IEEE 802.3 Standard MAC, and the Binary Exponential Back-off(BEB) algorithm is replaced by the proposed algorithm. From the view of normalized mean packet transmission delay time, the controller implemented here can be applicable to the office-automation system, and the factory-and laboratory-automation environment where the limited time criterion is very significant.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.4
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• pp.710-717
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• 1997

An investigation made of fabric strength & elongation and the lock stitch seam strength & elongation by stitch density (N1.5; 26 stitches/3 cm, N2.0; 19 stitches/3 cm, N2.5; 14 stitches/3cm) depending on methods of. sample prepariation (angle variations of unseamed sample and overlapping way of seamed sample) It found maximum stitch density that results of the seam strength test was highist in each angle of bias. The results obstained were as follows: 1. As the results of fabric strength and elongation tests as a function of angle of bias, breaking strength were that warp and weft angles (0$^{\circ}$, 90$^{\circ}$) were much higher than bias angles (20$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$, 60$^{\circ}$) . And otherwise breaking elongation were that 45$^{\circ}$ angle of bias were highest and were that the warp & weft way were lower. 2. As the results of the seam strength tests by the stitch density under samples of same angles, the maximum stitch density were those; under 0$^{\circ}$/0$^{\circ}$, 60$^{\circ}$/60$^{\circ}$:F1, F2-N2.0, F3-N1.5, under 20$^{\circ}$/20$^{\circ}$, 30$^{\circ}$/30$^{\circ}$, 45$^{\circ}$/45$^{\circ}$: F1-N2.5, F2-N2.0, F3-N1.5, under 90$^{\circ}$/90$^{\circ}$: F1, F2, F3-N1.5. 3. As the results of the seam strength tests by the stitch density under samples of symmetry angles, the maximum stitch density were those; under 20$^{\circ}$/-20$^{\circ}$, 30$^{\circ}$/-30$^{\circ}$, 60$^{\circ}$/-60$^{\circ}$: F1, F3-N1.5, F2-N2.0, under 45$^{\circ}$/-45$^{\circ}$: F1, F2-N2.0, F3-N1.5.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.197-204
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• 2004

The temporary power installations are to be used for temporarily supplying power during work at construction sites and have a minimum of protective devices to differ from permanent installations. There are many risk factors caused by loose working environments, deterioration of installations at construction sites. To analyze risk factors of temporary power installations, the investigation and the questionnaire were carried out side by side for power receiving system patch and panel boards, and were performed by researcher, the related expert, engineer of Korea Electrical Safety Corporation all over the country. The objects were variable such as an airport, an apartment, a municipal playground As a result, there are many problems such as a bad lock, poor protection of charging department. Solvable methods are improvement of the related regulation safety education, safety check and so on. In the future, the analytical data can be applied to prevent the electrical shock at construction site, and can be used to stabilize electrical installations.

• Journal of KIISE:Databases
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• v.30 no.4
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• pp.397-407
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• 2003

Transactions of updating spatial dta with mobile clients are log transactions because a user disconnected from a server surveys real features and updates them. In this environment, it is appropriate to exploit the optimistic approach based on the validation test in order to control the concurrency of transactions. On the contrary, the pessimistic concurrency control scheme makes transactions wait for a long time due to the lock. In this paper, we propose the surrogate transaction model and implement its manager for the S-S-M(Server-Surrogate PC-Mobile Client) structure which is appropriate for updating spatial data in mobile environments. In the S-S-M structure, the mobile client communicates with the server by the surrogate PC. We extend the validation condition in consideration of spatial relationships between spatial objects in this model. We also present the commit protocol where the user of a surrogate PC adjusts objects of the conflicted surrogate transaction to minimize costs for the abortion of the transaction.

• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.154-159
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• 2013

Objectives: The aim of this study was to compare the cleaning efficacy of different final irrigation regimens in canal and isthmus of mandibular molars, and to evaluate the influence of related variables on cleaning efficacy of the irrigation systems. Materials and Methods: Mesial root canals from 60 mandibular molars were prepared and divided into 4 experimental groups according to the final irrigation technique: Group C, syringe irrigation; Group U, ultrasonics activation; Group SC, VPro StreamClean irrigation; Group EV, EndoVac irrigation. Cross-sections at 1, 3 and 5 mm levels from the apex were examined to calculate remaining debris area in the canal and isthmus spaces. Statistical analysis was completed by using Kruskal-Wallis test and Mann-Whitney U test for comparison among groups, and multivariate linear analysis to identify the significant variables (regular replenishment of irrigant, vapor lock management, and ultrasonic activation of irrigant) affecting the cleaning efficacy of the experimental groups. Results: Group SC and EV showed significantly higher canal cleanliness values than group C and U at 1 mm level (p < 0.05), and higher isthmus cleanliness values than group U at 3 mm and all levels of group C (p < 0.05). Multivariate linear regression analysis demonstrated that all variables had independent positive correlation at 1 mm level of canal and at all levels of isthmus with statistical significances. Conclusions: Both VPro StreamClean and EndoVac system showed favorable result as final irrigation regimens for cleaning debris in the complicated root canal system having curved canal and/or isthmus. The debridement of the isthmi significantly depends on the variables rather than the canals.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.11
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• pp.145-156
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• 2018

Urban campus, one of the main urban facilities, is the representative place that is struggling with 'gridlock'. Due to privatization of space among different departments and space shortages, gridlock has been occurring as a result. The urban campus trying to solve this problem by changing the quality of space, especially the structure of the shared space, which is expected to be the solution to the grid lock problem. The main purpose of this study is to investigate the structural change in the university's shared space based on paradigm transition. The theoretical consideration is to analyze the spatial characteristics of university shared space that appear at different stages through a new perspective that compares the gridlock phenomenon and the shared paradigm. The framework of the analysis of the shared space, which has recently been restructured, is classified into the spatial characteristics of collaborative space, the creative space, and the common/complex space. In addition, these spatial characteristics are again analyzed through the division of legislative facility classification, management governance subject, area, building location and layout, exposure to the outside as well as the analysis of student and staff entry and exit, sharing structure of site and space, and the classification of program characteristics. The results are as follows: The restructured space is systemized so that the management governance of each space would be connected to each other to share information and space. Furthermore, the spatial boundary between colleges or between campus spaces are not only physically, but categorically clear. The restructured space has semi (or in-between)-spatial characteristics such as the intersection in inside and outside of the pedestrian's circulation and the mixture of programs. This study could serve as principal references in presenting the systematic analysis of directions of the shared spatial structure for the urban campus where new educational space is required due to the changes in the university system.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.491-500
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• 2020

The present study proposes a time domain model for the Vortex-induced Vibration (VIV) simulation of a catenary riser under the combination of the current and oscillatory flow induced by vessel motion. In this model, the hydrodynamic force of VIV comprises excitation force, hydrodynamic damping and added mass, which are taken as functions of the non-dimensional frequency and amplitude ratio. The non-dimensional frequency is related with the response frequency, natural frequency, lock-in range and the fluid velocity. The relatively oscillatory flow induced by vessel motion is taken into account in the fluid velocity. Considering that the added mass coefficient and the non-dimensional frequency can affect each other, an iterative analysis is conducted at each time step to update the added mass coefficient and the natural frequency. This model is in detail validated against the published test models. The results show that the model can reasonably reflect the effect of the added mass coefficient on the VIV, and can well predict the riser's VIV under stationary and oscillatory flow induced by vessel motion. Based on the model, this study carries out the VIV simulation of a catenary riser with harmonic vessel motion. By analyzing the bending moment near the touchdown point, it is found that under the combination of the ocean current and oscillatory flow the vessel motion may decrease the VIV response, while increase the excited frequencies. In addition, the decreasing rate of the VIV under vessel surge is larger than that under vessel heave at small vessel motion velocity, while the situation becomes opposite at large vessel motion velocity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.3
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• pp.478-485
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• 2021

An injection locking technology of a semiconductor laser is a promising technology to generate optical complex signals by adjusting optical injection parameters. The extraction of the precise injection parameters plays a key role in the generation of the optical complex signal. Rate equations of semiconductor lasers under optical injection are commonly used to map the injection parameters and the corresponding optical complex signal. The accuracy of the generated optical complex signal on the injection parameters is limited since the rate equations require a locking map-based interpolation method. We propose a novel analytic method, namely rate equation-based direct extraction method, to directly calculate the injection parameters without relying on the locking map-based interpolation method. We achieved 103-times improvement of the signal accuracy by using the proposed method compared to locking-map based interpolation method.