• Title/Summary/Keyword: Dispersion effects

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Characteristics of Intra and Inter-Regional Population Mobility Resulting from Innovative City Development (혁신도시 건설에 따른 권역내·외 인구이동 특성)

  • Seong-Won KANG;Tae-Heon MOON;Hye-Lim KIM
    • Journal of the Korean Association of Geographic Information Studies
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    • v.26 no.4
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    • pp.1-16
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    • 2023
  • In 2005, the selection of 10 innovation cities was completed, and since 2013, public institutions began relocating to innovation cities. As a policy aimed at promoting balanced regional development, there were significant expectations from the regions. However, although the population moving to innovation cities has increased, it remains to be seen how much inflow is from the capital region and what spatial characteristics exist nationwide. Therefore, this study aims to analyze whether the innovation cities are fulfilling their roles by examining the patterns of inflow from the capital region and the spatial characteristics, and to reassess the policy direction for future innovation cities. We utilized the Microdata Integrated Service (MDIS) provided by Statistics Korea from 2013 to 2021. For the data collection reasons, we focused on analyzing the three cities. The results showed that in the initial stages of innovation city development, there was a significant influx of population from the capital region, leading to some effects on population dispersion and balanced regional development. However, over time, a phenomenon emerged where more people started to move back to the capital region, indicating a problematic trend. Furthermore, the Gyeongbuk Innovation City and Gwangju-Jeonnam Innovation City showed similarities in terms of reasons for migration, age of householder, and number of household members. However, the Gyeongnam Innovation City exhibited distinct characteristics compared to the other two cities. While the reasons for this phenomenon may be diverse, the current situation suggests that the goal of achieving "balanced national development" has reached its limits. Therefore, urgent measures need to be taken for improvement that take regional characteristics into account. Furthermore, in designing the second phase of the public institution relocation plan is required to avoid repeating the same issues and ensure a more thoughtful approach.

Shipboard Verification Test of Onboard Carbon Dioxide Capture System (OCCS) Using Sodium Hydroxide(NaOH) Solution (가성소다(NaOH) 용액을 이용한 선상 이산화탄소 포집 장치의 선박 검증시험)

  • Gwang Hyun Lee;Hyung Ju Roh;Min woo Lee;Won Kyeong Son;Jae Yeoul Jeong;Tae-Hong Kim;Byung-Tak NAM;Jae-Ik Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.61 no.1
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    • pp.51-60
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    • 2024
  • Hi Air Korea and Hanwha ocean are currently developing an Onboard Carbon dioxide Capture System (OCCS) to absorb CO2 emitted from ship's engine using a sodium hydroxide(NaOH) solution, and converting the resulting salt into a solid form through a chemical reaction with calcium oxide (CaO). The system process involves the following steps; 1)The reaction of CO2 gas absorption in water, 2)The reaction between carbonic acid (H2CO3) and NaOH solution to produce carbonate or bicarbonate, and 3)The reaction between carbonate or bicarbonate and CaO to form calcium carbonate (CaCO3). And ultimately, the solid material, CaCO3, is separated and discharged using a separator. The OCCS has been installed on an ship and the test results have confirmed significant reduction effects of CO2 in the ship's exhaust gas. A portion of the exhaust gas emitted from the engine was transferred to the OCCS using a blower. The flow rate of the transferred gas ranged from 800 to 1384 m3/hr, and the CO2 concentration in the exhaust gas was 5.1 vol% for VLSFO, 3.7 vol% for LNG and a 12 wt% NaOH solution was used. The results showed a CO2 capture efficiency of approximately 42.5 to 64.1 vol% and the CO2 capture rate approximately 48.4 to 52.2kg/hr. Additionally, to assess the impact of the discharged CaCO3on the marine ecosystem, we conducted "marine ecotoxicity test" and performed Computational Fluid Dynamics (CFD) analysis to evaluate the dispersion and dilution of the discharged effluent.

The Effects of Sentiment and Readability on Useful Votes for Customer Reviews with Count Type Review Usefulness Index (온라인 리뷰의 감성과 독해 용이성이 리뷰 유용성에 미치는 영향: 가산형 리뷰 유용성 정보 활용)

  • Cruz, Ruth Angelie;Lee, Hong Joo
    • Journal of Intelligence and Information Systems
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    • v.22 no.1
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    • pp.43-61
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    • 2016
  • Customer reviews help potential customers make purchasing decisions. However, the prevalence of reviews on websites push the customer to sift through them and change the focus from a mere search to identifying which of the available reviews are valuable and useful for the purchasing decision at hand. To identify useful reviews, websites have developed different mechanisms to give customers options when evaluating existing reviews. Websites allow users to rate the usefulness of a customer review as helpful or not. Amazon.com uses a ratio-type helpfulness, while Yelp.com uses a count-type usefulness index. This usefulness index provides helpful reviews to future potential purchasers. This study investigated the effects of sentiment and readability on useful votes for customer reviews. Similar studies on the relationship between sentiment and readability have focused on the ratio-type usefulness index utilized by websites such as Amazon.com. In this study, Yelp.com's count-type usefulness index for restaurant reviews was used to investigate the relationship between sentiment/readability and usefulness votes. Yelp.com's online customer reviews for stores in the beverage and food categories were used for the analysis. In total, 170,294 reviews containing information on a store's reputation and popularity were used. The control variables were the review length, store reputation, and popularity; the independent variables were the sentiment and readability, while the dependent variable was the number of helpful votes. The review rating is the moderating variable for the review sentiment and readability. The length is the number of characters in a review. The popularity is the number of reviews for a store, and the reputation is the general average rating of all reviews for a store. The readability of a review was calculated with the Coleman-Liau index. The sentiment is a positivity score for the review as calculated by SentiWordNet. The review rating is a preference score selected from 1 to 5 (stars) by the review author. The dependent variable (i.e., usefulness votes) used in this study is a count variable. Therefore, the Poisson regression model, which is commonly used to account for the discrete and nonnegative nature of count data, was applied in the analyses. The increase in helpful votes was assumed to follow a Poisson distribution. Because the Poisson model assumes an equal mean and variance and the data were over-dispersed, a negative binomial distribution model that allows for over-dispersion of the count variable was used for the estimation. Zero-inflated negative binomial regression was used to model count variables with excessive zeros and over-dispersed count outcome variables. With this model, the excess zeros were assumed to be generated through a separate process from the count values and therefore should be modeled as independently as possible. The results showed that positive sentiment had a negative effect on gaining useful votes for positive reviews but no significant effect on negative reviews. Poor readability had a negative effect on gaining useful votes and was not moderated by the review star ratings. These findings yield considerable managerial implications. The results are helpful for online websites when analyzing their review guidelines and identifying useful reviews for their business. Based on this study, positive reviews are not necessarily helpful; therefore, restaurants should consider which type of positive review is helpful for their business. Second, this study is beneficial for businesses and website designers in creating review mechanisms to know which type of reviews to highlight on their websites and which type of reviews can be beneficial to the business. Moreover, this study highlights the review systems employed by websites to allow their customers to post rating reviews.

Effects of Mowing (Beolcho) Timing and Height on Growth Characteristics of Zoysia japonica and Z. matrella before Chuseok (추석 전 잔디 깍기(벌초) 시기 및 높이에 따른 들잔디와 금잔디의 생육)

  • Chang, Seog-Won;Koo, Jun-Hak;Sung, Chang-Hyun;Lee, Jeong-Ho;Park, Sho-Jun;Jee, Jae-Uk;Youn, Jeong-Ho
    • Weed & Turfgrass Science
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    • v.7 no.2
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    • pp.140-147
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    • 2018
  • In Korea, mowing the grass of a grave (Beolcho) is a very important event preceded by Chuseok (Korean thanks giving day) and Si-Hyang (annual ancestral feast). Because Beolcho usually takes place one or two weeks before Chuseok, the traffic accidents on roads are getting worse and safety accidents are getting more and more. Erroneous Beolcho methods can cause the soil to be exposed and cause the loss of soil or the low shoot density of graveyard grass or weed occurrence. Therefore, the dispersion of the Beolcho timing and the approprite method can be import issues. The present study assessed the effects of grass mowing timing and height before Chuseok on the growth of Zoysia japonica and Z. matrella. The mowing timing was evaluated at 1 week, 2 weeks, 3 weeks, and 4 weeks before Chuseok, and the mowing height differently according to the two type of grass. In Z. japonica, the faster mowing before Chuseok, the longer the plant height, and the coverage rate and shoot density were higher. In Z. matrella, the faster mowing, the longer the shoot length, but the coverage rate and shoot density did not show any difference or tendency. As compared to Z. japonica, the plant height of Z. matrella was kept short regardless of the time of mowing. In both grasses, the plant height was shortened when mowing was done at low cutting height, but the coverage rate and shoot density were decreased. In addition, it was shown that it is advantageous to maintain the shoot density of graveyard lawn by 40-50 mm or 30-40 mm cutting above the ground for Z. japonica or Z. matrella, respectively.

Initial results from spatially averaged coherency, frequency-wavenumber, and horizontal to vertical spectrum ratio microtremor survey methods for site hazard study at Launceston, Tasmania (Tasmania 의 Launceston 시의 위험 지역 분석을 위한 공간적 평균 일관성, 주파수-파수, 수평과 수직 스펙트럼의 비율을 이용한 상신 진동 탐사법의 일차적 결과)

  • Claprood, Maxime;Asten, Michael W.
    • Geophysics and Geophysical Exploration
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    • v.12 no.1
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    • pp.132-142
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    • 2009
  • The Tamar rift valley runs through the City of Launceston, Tasmania. Damage has occurred to city buildings due to earthquake activity in Bass Strait. The presence of the ancient valley, the Tamar valley, in-filled with soft sediments that vary rapidly in thickness from 0 to 250mover a few hundreds metres, is thought to induce a 2D resonance pattern, amplifying the surface motions over the valley and in Launceston. Spatially averaged coherency (SPAC), frequency-wavenumber (FK) and horizontal to vertical spectrum ratio (HVSR) microtremor survey methods are combined to identify and characterise site effects over the Tamar valley. Passive seismic array measurements acquired at seven selected sites were analysed with SPAC to estimate shear wave velocity (slowness) depth profiles. SPAC was then combined with HVSR to improve the resolution of these profiles in the sediments to an approximate depth of 125 m. Results show that sediments thicknesses vary significantly throughout Launceston. The top layer is composed of as much as 20m of very soft Quaternary alluvial sediments with a velocity from 50 m/s to 125 m/s. Shear-wave velocities in the deeper Tertiary sediment fill of the Tamar valley, with thicknesses from 0 to 250m vary from 400 m/s to 750 m/s. Results obtained using SPAC are presented at two selected sites (GUN and KPK) that agree well with dispersion curves interpreted with FK analysis. FK interpretation is, however, limited to a narrower range of frequencies than SPAC and seems to overestimate the shear wave velocity at lower frequencies. Observed HVSR are also compared with the results obtained by SPAC, assuming a layered earth model, and provide additional constraints on the shear wave slowness profiles at these sites. The combined SPAC and HVSR analysis confirms the hypothesis of a layered geology at the GUN site and indicates the presence of a 2D resonance pattern across the Tamar valley at the KPK site.

Seasonal Circulation and Estuarine Characteristics in the Jinhae and Masan Bay from Three-Dimensional Numerical Experiments (3차원 수치모의 실험을 통한 진해·마산만의 계절별 해수순환과 염하구 특성)

  • JIHA KIM;BYOUNG-JU CHOI;JAE-SUNG CHOI;HO KYUNG HA
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.29 no.2
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    • pp.77-100
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    • 2024
  • Circulation, tides, currents, harmful algal blooms, water quality, and hypoxic conditions in Jinhae-Masan Bay have been extensively studied. However, these previous studies primarily focused on short-term variations, and there was limited detailed investigation into the physical mechanisms responsible for ocean circulation in the bays. Oceanic processes in the bays, such as pollutant dispersal, changes on a seasonal time scale. Therefore, this study aimed to understand how the circulation in Jinhae-Masan Bay varies seasonally and to examine the effects of tides, winds, and river discharges on regional ocean circulation. To achieve this, a three-dimensional ocean circulation model was used to simulate circulation patterns from 2016 to 2018, and sensitivity experiments were conducted. This study reveals that convective estuarine circulation develops in Jinhae and Masan Bays, characterized by the inflow of deep oceanic water from the Korea Strait through Gadeoksudo, while surface water flows outward. This deep water intrusion divides into northward and westward branches. In this study, the volume transport was calculated along the direction of bottom channels in each region. The meridional water exchange in the eastern region of Jinhae Bay is 2.3 times greater in winter and 1.4 times greater in summer compared to that of zonal exchange in the western region. In the western region of Jinhae Bay, the circulation pattern varies significantly by season due to changes in the balance of forces. During winter, surface currents flow southward and bottom currents flow northward, strengthening the north-south convective circulation due to the combined effects of northwesterly winds and the slope of the sea surface. In contrast, during summer, southwesterly winds cause surface seawater to flow eastward, and the elevated sea surface in the southeastern part enhances northward barotropic pressure gradient intensifying the eastward surface flow. The density gradient and southward baroclinic pressure gradient increase in the lower layer, causing a strong westward inflow of seawater from Gadeoksudo, enhancing the zonal convective circulation by 26% compared to winter. The convective circulation in the western Jinhae Bay is significantly influenced by both tidal current and wind during both winter and summer. In the eastern Jinhae Bay and Masan Bay, surface water flows outward to the open sea in all seasons, while bottom water flows inward, demonstrating a typical convective estuarine circulation. In winter, the contributions of wind and freshwater influx are significant, while in summer, the influence of mixing by tidal currents plays a major role in the north-south convective circulation. In the eastern Jinhae Bay, tidally driven residual circulation patterns, influenced by the local topography, are distinct. The study results are expected to enhance our understanding of pollutant dispersion, summer hypoxic events, and the abundance of red tide organisms in these bays.

A Study on the Breeding Density and Diet of Magpie Pica pica in Jeju Island1a (제주도에 서식하는 까치 Pica pica의 번식 밀도 및 식이물에 관한 연구)

  • Park, Joo-Yeon;Kim, Byoung-Soo;Oh, Hong-Shik
    • Korean Journal of Environment and Ecology
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    • v.22 no.6
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    • pp.648-657
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    • 2008
  • This research was conducted to investigate the breeding density and seasonal food items of the magpies in Jeju Island and the near-manned islets. The examination of nest distribution to determine breeding density was performed during breeding season from February 2006 to April 2008, and that of food items from May 2006 to February 2008. A total of 2,113 nests were found across Jeju Island, the average density was $1.33\;nest/km^2$, and the magpies were distributed up to 600 meters above the sea level. The nest density was the highest in the central areas of Jeju Island, with 688 nests at $3.61\;nest/km^2$, while that in the eastern areas was the lowest, with 214 nests at $0.66\;nest/km^2$. In terms of the number of nests depending on the height above the sea level, 1,172 nests, which was equivalent to the density of $1.85\;nest/km^2$, was observed below 100m and highest among the intervals of height, but 16 nests found at 500-600m were the lowest, corresponding to $0.20\;nest/km^2$. The number of nests found in the manned islets near Jeju Island was eight in Biyang-do with the density of $15.38\;nest/km^2$, nine in U-do with $1.49\;nest/km^2$, and one in Gapa-do with $1.15\;nest/km^2$, whereas none of nests were observed in Mara-do. The contents of stomach consisted of 17 types of prey sources including countless bones, eggshells, plants, and seed, most of which were the individuals of the order Coleoptera. In spring and summer, the foraging frequency for invertebrate animals such as insects was high, but less than 30% in winter. In contrast, the magpies preyed upon plants and seeds at the frequency of 10% and 30%, respectively, in spring, while the foraging frequencies for both of them were 100% in winter and higher than any of other seasons. Eggshells and bones of birds were also detected infrequently. If the density of the magpies, which may play role as the upper predator within the ecosystem, increases, it would be expected to affect directly the reduction of the number of the species and population of endemic animals such as small birds and reptiles, etc. Therefore, it is considered that long-term monitoring for the density of the magpies and precaution is prerequisite to minimize adverse effects on ecosystem.

The Ownership Structure of Korea's Big Business Conglomerates and Its Policy Implications (우리나라 기업집단(企業集團)의 소유(所有)·경영구조(經營構造)와 정책대응(政策對應))

  • Yoo, Seong-min
    • KDI Journal of Economic Policy
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    • v.14 no.1
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    • pp.3-36
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    • 1992
  • "Corporate control by owners" characterizes the current structure of ownership, control and management of big business groups in Korea. It has become an ever more serious obstacle for the Korean economy to end its distinctive "personal capitalism" and to transform the current system into people's capitalism. The current issue, the deconcentration of ownership, through the course of heated debates should be treated from an integrated perspective. That is, the debate should center on the concentration of economic power and it effects on national economy, instead of sticking to the issue of ownership-control issue per se. This paper, by referring to the historical experiences and development paths which advanced countries have already traveled, analyzes the respective aspects of the concentration issue in a rather descriptive and taxonomist manner - market concentration, business diversification, ownership concentration, integrated management of conglomerates, i.e., managing in groups' unit, and the roles of financial institutions. The government policies against the concentration of economic power have so far focused on the size of big business groups and their diversification activities. The two major policy measures are restrictions on cross-ownership and excess capital investment by big business groups, and controls on their credit deals. This paper strongly suggests that the government should change its current priorities in targeting its policies against concentration. The government should reduce the regulations on size and diversification, and focus its policies on substantial dispersion of corporate ownership. The efficacy of government intervention in the management and control of business enterprises seems quite dubious and even anachronistic given the extent of maturity of Korean firms. Therefore, it should be noted that the current regulation-oriented stance taken by the government against the management style of big business groups should be suppressed, as it has assumed some a priori and typical pattern in advance in directing big business groups, such as independent and specialized management in respective firms' unit. This paper, also, raises the need for introducing new regulations on inter-sectoral diversifications between finance, industry and the press.

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A Research on Effective Combination of Elementary Math and Game (초등수학과 게임의 효과적인 접목을 위한 연구)

  • Kim, Ge-won
    • Cartoon and Animation Studies
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    • s.37
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    • pp.393-411
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    • 2014
  • The volume of world market for serious game in year 2015 is expected to be about 9.6 trillion, and the volume of educational serious game market is expected to surpass half of the whole serious game market. In Korea, the development of game for educational purpose has dominated around the education enterprises since late 90s. In 2008, 'Serious Game Forum' was founded led by the Ministry of Culture, Sports, and Tourism with experts from many fields in the society and there were progressing of making policies and plans for potential development of the serious game industry, but the effects were not successful than expected. In 2012, the Ministry of Education, Science, and Technology announced commercialization policy of digital textbook by 2015 and the serious game for educational purpose got attention again. Then, the serious game market became more vigorous with the dispersion of smart devices.13) As a result, the serious games on the smart devices or interlocking between the online and smart devices became an important issue in development rather than the online only serious games. Math field has international competitive power through export in the educational serious game market which takes more than half of the serious game market. Therefore, developing serious game for math education is a good area to raise competitiveness in domestic and international game industries. Moreover, it has no received preferences from students and parents although it has high potential for positive change of individuals and society. The reason is that students recognize it as educational content rather than a game and they avoid it, while parents recognize it as game but not an education. This phenomenon happens because the game elements and educational elements are not properly mixed but focused only on education or emphasized only the fun factors of game when it was developed. Therefore, the purpose of this research is to suggest a direction of developing serious games effectively combining with elementary math for elementary students to get interested in math while playing games. The research will analyze the current elementary math textbooks and find contents which may be combined with the game genre that elementary students enjoy playing these days. This research received advice from serious game developers and math education expert group to reflect the inclination of elementary school students, and respond to the demands from parents and educational institutions, and suggested a direction of developing serious games for effective math education.

Retrieval of Pollen Optical Depth in the Local Atmosphere by Lidar Observations (라이다를 이용한 지역 대기중 꽃가루의 광학적 두께 산출)

  • Noh, Young-Min;Lee, Han-Lim;Mueller, Detlef;Lee, Kwon-Ho;Choi, Young-Jean;Kim, Kyu-Rang;Choi, Tae-Jin
    • Korean Journal of Remote Sensing
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    • v.28 no.1
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    • pp.11-19
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    • 2012
  • Air-borne pollen, biogenically created aerosol particle, influences Earth's radiative balance, visibility impairment, and human health. The importance of pollens has resulted in numerous experimental studies aimed at characterizing their dispersion and transport, as well as health effects. There is, however, limited scientific information concerning the optical properties of airborne pollen particles contributing to total ambient aerosols. In this study, for the first time, optical characteristics of pollen such as aerosol backscattering coefficient, aerosol extinction coefficient, and depolarization ratio at 532 nm and their effect to the atmospheric aerosol were studied by lidar remotes sensing technique. Dual-Lidar observations were carried out at the Gwangju Institute of Science & Technology (GIST) located in Gwagnju, Korea ($35.15^{\circ}E$, $126.53^{\circ}N$) for a spring pollen event from 5 to 7 May 2009. The pollen concentration was measured at the rooftop of Gwangju Bohoon hospital where the building is located 1.0 km apart from lidar site by using Burkard trap sampler. During intensive observation period, high pollen concentration was detected as 1360, 2696, and $1952m^{-3}$ in 5, 6, and 7 May, and increased lidar return signal below 1.5km altitude. Pollen optical depth retrieved from depolarization ratio was 0.036, 0.021, and 0.019 in 5, 6, and 7 May, respectively. Pollen particles mainly detected in daytime resulting increased aerosol optical depth and decrease of Angstrom exponent.