• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.5
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• pp.365-373
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• 2013

Tile caching technology is a commonly used method that optimizes the delivery of map imagery across the internet in modern WebGIS systems. However the poor performance of the map tile cache update is one of the major causes that hamper the wider use of this technique for datasets with frequent updates. In this paper, we introduce a new algorithm, namely, Partial Area Cache Update (PACU) that significantly minimizes redundant update of map tiles where the update frequency of source map data is very large. The performance of our algorithm is verified with the cadastral map data of Pyeongtaek of Gyeonggi Province, where approximately 3,100 changes occur in a day among the 331,594 parcels. The experiment results show that the performance of the PACU algorithm is 6.6 times faster than the ESRI ArcGIS SERVER$^{(r)}$. This algorithm significantly contributes in solving the frequent update problem and enable Web Map Tile Services for data that requires frequent update.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.49-62
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• 2024

Reckless development of the underground by rapid urbanization causes inspection delay on replacement of existing structure and installation new facilities. However, frequent accidents occur due to deviation in construction design planned by inaccurate location information of underground structure. Meanwhile, the electrical resistivity survey, knowns as non-destructive method, is based on the difference in the electric potential of electrodes to measure the electrical resistance of ground. This method is significantly advanced with multi-electrode and deep learning for analyzing strata. However, there is no study to quantitatively assess change in electrical resistance according to geometric conditions of structures. This study evaluates changes in electrical resistance through geometric parameters of electrodes and structure. Firstly, electrical resistance numerical module is developed using generalized mesh occurring minimal errors between theoretical and numerical resistance values. Then, changes in resistances are quantitatively compared on geometric parameters including burial depth, diameter of structure, and distance electrode and structure under steady current condition. The results show that higher electrical resistance is measured for shallow depth, larger size, and proximity to the electrode. Additionally, electric potential and current density distributions are analyzed to discuss the measured electrical resistance around the terminal electrode and structure.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.3
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• pp.13-22
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• 2012

Even with its significant influence on the dynamic analysis and foundation design of structures, sometimes the soil-structure interaction has been ignored during the design process. One of the reasons is due to the fact that the modeling procedures are too complicated to meet the requirements in practice. In this study, using the Cali(IT)2 building in California with high and frequent seismic activities, the analysis differences for different boundary conditions are reviewed. The Beam on Nonlinear Winkler Foundation Model, one of the foundation modeling methods, is modified for easy use by the Linear Matrix Inequalities Model Reduction Technique. The product of the proposed process is applied to create the Finite Element Model. The results show fairly good agreement with the real data acquired from the Cal(IT)2 building.

• Ocean Systems Engineering
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• v.9 no.4
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• pp.409-422
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• 2019

Sloshing is a phenomenon which may lead to dynamic stability and damages on the local structure of the tank. Hence, several anti-sloshing devices are introduced in order to reduce the impact pressure and free surface elevation of liquid. A fixed baffle is the most prevailing anti-sloshing mechanism compared to the other methods. However, the additional of the baffle as the internal structure of the LNG tank can lead to frequent damages in long-term usage as this structure absorbs the sloshing loads and thus increases the maintenance cost and downtime. In this paper, a novel type of floating baffle is proposed to suppress the sloshing effect in LNG tank without the need for reconstructing the tank. The sloshing phenomenon in a membrane type LNG tank model was excited under sway motion with 30% and 50% filling condition in the model test. A regular motion by a linear actuator was applied to the tank model at different amplitudes and constant period at 1.1 seconds. Three pressure sensors were installed on the tank wall to measure the impact pressure, and a high-speed camera was utilized to record the sloshing motion. The floater baffle was modeled on the basis of uniform-discretization of domain and tested based on parametric variations. Data of pressure sensors were collected for cases without- and with-floating baffle. The results indicated successful reduction of surface run-up and impulsive pressure by using a floating baffle. The findings are expected to bring significant impacts towards safer sea transportation of LNG.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.12
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• pp.540-551
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• 2008

Today's microprocessor designs are not free from temperature as well as power consumption. As processor technology scales down, an on-chip circuitry increases power density, which incurs excessive temperature (hotspot) problem. To tackle thermal problems cost-effectively, Dynamic Thermal Management (DTM) has been suggested: DTM techniques have benefits of thermal reliability and cooling cost. However, they require trade-off between thermal control and performance loss. This paper proposes a dual integer register file structure to minimize the performance degradation due to DTM invocations. In on-chip thermal control, the most important functional unit is an integer register file. It is the hotspot unit because of frequent read and write data accesses. The proposed dual integer register file migrates read data accesses by adding an extra register file, thus reduces per-unit dynamic power dissipation. As a result, the proposed structure completely eliminates localized hotspots in the integer register file, resulting in much less performance degradation by average 13.35% (maximum 18%) improvement compared to the conventional DTM architecture.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.6
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• pp.13-20
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• 2009

The purpose of this study is to analyze the configuration and properties of university campus cores for systematic approach and planning through space syntax based on master plans of 55 universities in Korea. The results of this study showed that: first, the campus cores were classified into 10 types through axial map analysis. They were '一 type', '二 type', 'ㄱ type', 'T type', '+ type', 'radiation type', 'grid type', 'polygon type', 'tree structure type' and 'combination type'.(table 7) The frequency of '一 type' was the highest by 27.2%, and 'radiation type' was the next by 14.5%; second, the integration value was 2.03(+ type), te90(grid type), te75(ㄱ type), te74(一 type), te67(二 type), te63(T type), te46(polygon type), te347(tree structure type) and te343(radiation type).(table 9) We could categorize the 'radiation type' and the 'tree structure type' as the first group, the 'polygon type' as the second group, the 'T type', the '二 type', the '一 type', and the 'ㄱ type' as the third group, the 'grid type' as the fourth group, the '+ type' as the fifth group; third, cases that the integration value of access road was very low(58.2%) was much more frequent than that of very high(32.7%); fourth, the most important space in the campus core were as follows: library and media center(18.1%), administration buildings and headquarters(15.7%), student center(15.7%), lecturing building(13.9%), streets and squares(13.3%).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.307-316
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• 2003

Fish assemblage structure in a sheltered shallow water in the Southern Coast of Korea was examined monthly. Sampling was conducted in Doam Bay using a beam trawl between March 2001 and February 2001. A total of 53 fish species from 33 families were caught. Pinkgray goby (Chaeturichthys hexanema), ponyfish (Leiognathus nuchalis) and yellowfin goby (Acanthogobius favimanus) were the most frequent species, comprised 67.4％ of the total numbers captured. Snailfish (Liparis tanakai), yellowfin goby (Acanthogobius flavimanus) and pinkgray goby (Chaeturichthys hexanema) represented 50.8％ of the total biomass. While total abundance (number of individuals) and biomass were high in autumn and winter, species richness (number of species) and diversity were high in spring. Cluster analysis, based on monthly abundance data of the 14 most frequent species, showed that the species were separated into three different groups. Group A composed of pinkgray goby, yellowfin goby, robust tonguefish (Cynoglossus robustus) and scaly hairfin anchovy (Setipinna taty), which were year-round residents, and devil flathead (Onigocia spinosa), Red dragonet (Repomucenus lunatus) and ponyfish, which were abundant in autumn, group B surmullet (Upeneus japonicus), hairtail (Trichiurus lepturus) and gaff-topsail goby (Cryptocentrus filifer), which were abundant in summer, and group C grassfish (Liparis tanakai), spotted velvefish (Erisphex pottii), chameleon goby (Tridentiger trigonocephalus) and Richardson dragonet (Repomucenus richardsonii), which were abundant in winter and spring. A seasonal homogeneity of fish assemblage indicates that overall fish assemblage in Dom Bay is largely controlled by year-round residents.

• Journal of the Korean Geographical Society
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• v.31 no.2
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• pp.198-212
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• 1996

In celebrating a half century history of the Korean Geographical Society, this paper is concerned about research trends of the urban geography in Korea by reviewing of 449 papers and 15 books mainly in an urban geography field. The findings are summarized as follows: (1) The development of the urban geography in Korea has several stages; \circled1 The launching stage just after 1945; \circled2 the premature stage in the 1960s; \circled3 the taking-off stage in the 1970s; \circled4 the maturing stage in the 1980s; and \circled5 culminating stage in the as of 1990s. (2) The earlier studies had a few limited research themes without major debating issues. In the 1970s, various research themes had been introduced in the urban geography. More diverse themes have been studied in urban geography after the 1980s. The major themes in the urban geography included urbanization, urban structure, urban system, urban economic structure and so on. (3) The most frequent research area for the Korean urban geographers has been the Seoul metropolitan area followed by Kyongsang-Province region. Outside Korea, the most frequent research areas are the American cities followed by the cities of Japan, Canada, and France. (4) The urban geography in Korea has played a major role in introducing the quantitative methods and techniques into geography. For example over 30.5% out of papers in urban geography has taken the quantitative techniques in the past 35 years during the 1960-1994 period. The papers inside urban geography have counted more than 60 percent from research papers in major university journals and took 34.6 percent from the papers of the Journal of Korean Geographical Society.

• Sijohaknonchong
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• v.19 no.1
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• pp.85-106
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• 2003

Recently, the sonnet and the shijo, each representing French and Korean formal poetries, are tend to be read with the eyes only, as were more accustomed to written literature. But even after almost three millennia of written literature and increased use of digitalized poems, poetry retains its appeal to the ear as well as to the eye. To read a poem only by eyes might be wrong because it is designed to be read aloud by mouth and understood by ear, and will decrease the aesthetic sense otherwise. It is essential to find the right way to recite a poem in this dramatically changed society, and is especially important when many shijos are changing into digitalized forms to adapt the new wave of our society. The sonnet and the shijo emphasize the importance of the harmony of sounds and rhythms with certain structure, and have their own prosodies. The emotions of the speaker in poems are expressed with words. When they are pronounced. each phoneme has its own phonemic characteristics. When comparing the The Broken Bell(Baudelaire) and Chopoong ga (Jong Seo Kim) in terms of prosody and phonetics. the speakers emotions are closely related with the phonetic structure of each word. In The Broken Bell, the phonetic value of rhymes, repeated phonemes, concentration of front and back vowels. rhythms of onesyllable words shape the overall image of this poem describing the productivity of bells as appose to the sterility of the soul. Chopoong ga also shows the determined and strong will of the speaker by frequent glottalized sounds. distribution and concentration of certain vowels. and frequent use of plosives. As you see in these examples, phones, beats, and rhythms are not the mere transmitter of meaning but possess their expressive values of their own and should be the first to be considered when reciting a poem.

• Journal of KIISE:Databases
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• v.31 no.3
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• pp.261-273
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• 2004

Advances in information and communication technologies have been creating new classes of applications in the area of databases. For example, in moving object databases, which track positions of a lot of objects, or stream databases, which process data streams from a lot of sensors, data Processed in such database systems are usually changed very rapidly and continuously. However, traditional database systems have a problem in processing these rapidly and continuously changing data because they suppose that a data item stored in the database remains constant until It is explicitly modified. The problem becomes more serious in the R-tree, which is a typical index structure for multidimensional data, because modifying data in the R-tree can generate cascading node splits or merges. To process frequent updates more efficiently, we propose a novel update technique for the R-tree, which we call the leaf-update technique. If a new value of a data item lies within the leaf MBR that the data item belongs, the leaf-update technique changes the leaf node only, not whole of the tree. Using this leaf-update manner and the leaf-access hash table for direct access to leaf nodes, the proposed technique can reduce update cost greatly. In addition, the leaf-update technique can be adopted in diverse variants of the R-tree and various applications that use the R-tree since it is based on the R-tree and it guarantees the correctness of the R-tree. In this paper, we prove the effectiveness of the leaf-update techniques theoretically and present experimental results that show that our technique outperforms traditional one.