• Journal of Intelligence and Information Systems
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• v.22 no.2
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• pp.81-96
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• 2016

As the internet has become widespread and easy to access everywhere, it is common for people to search information via online search engines such as Google and Naver in everyday life. Recent studies have used online search volume of specific keyword as a measure of the internet users' attention in order to predict disease outbreaks such as flu and cancer, an unemployment rate, and an index of a nation's economic condition, and etc. For stock traders, web search is also one of major information resources to obtain data about individual stock items. Therefore, search volume of a stock item can reflect the amount of investors' attention on it. The investor attention has been regarded as a crucial factor influencing on stock price but it has been measured by indirect proxies such as market capitalization, trading volume, advertising expense, and etc. It has been theoretically and empirically proved that an increase of investors' attention on a stock item brings temporary increase of the stock price and the price recovers in the long run. Recent development of internet environment enables to measure the investor attention directly by the internet search volume of individual stock item, which has been used to show the attention-induced price pressure. Previous studies focus mainly on Dow Jones and NASDAQ market in the United States. In this paper, we investigate the relationship between the individual investors' attention measured by the internet search volumes and stock price changes of individual stock items in the KOSDAQ market in Korea, where the proportion of the trades by individual investors are about 90% of the total. In addition, we examine the difference between industries in the influence of investors' attention on stock return. The internet search volume of stocks were gathered from "Naver Trend" service weekly between January 2007 and June 2015. The regression model with the error term with AR(1) covariance structure is used to analyze the data since the weekly prices in a stock item are systematically correlated. The market capitalization, trading volume, the increment of trading volume, and the month in which each trade occurs are included in the model as control variables. The fitted model shows that an abnormal increase of search volume of a stock item has a positive influence on the stock return and the amount of the influence varies among the industry. The stock items in IT software, construction, and distribution industries have shown to be more influenced by the abnormally large internet search volume than the average across the industries. On the other hand, the stock items in IT hardware, manufacturing, entertainment, finance, and communication industries are less influenced by the abnormal search volume than the average. In order to verify price pressure caused by investors' attention in KOSDAQ, the stock return of the current week is modelled using the abnormal search volume observed one to four weeks ahead. On average, the abnormally large increment of the search volume increased the stock return of the current week and one week later, and it decreased the stock return in two and three weeks later. There is no significant relationship with the stock return after 4 weeks. This relationship differs among the industries. An abnormal search volume brings particularly severe price reversal on the stocks in the IT software industry, which are often to be targets of irrational investments by individual investors. An abnormal search volume caused less severe price reversal on the stocks in the manufacturing and IT hardware industries than on average across the industries. The price reversal was not observed in the communication, finance, entertainment, and transportation industries, which are known to be influenced largely by macro-economic factors such as oil price and currency exchange rate. The result of this study can be utilized to construct an intelligent trading system based on the big data gathered from web search engines, social network services, and internet communities. Particularly, the difference of price reversal effect between industries may provide useful information to make a portfolio and build an investment strategy.

• Journal of Korean Society of Forest Science
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• v.73 no.1
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• pp.43-54
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• 1986

This study was carried out to investigate the influence of light intensity on the growth of Korean white pine (Pinus koraiensis) seedlings. The seedlings were grown under four different relative light intensities: 100%, 63%, 37%, and 19% of full sunlight by covering with saran screen on seed bed. The results obtained were summarized as follows; 1. The highest shoot elongation was found at 37% in relative light intensity (RLI) plot, and the best growth in root, seedling length and diameter increment appeared at 100% on RLI plot. Contribution rates of shading to growth in shoot elongation, root growth, seedling length, and diameter increment were 9.3%, 26.2%, 21.0%, and 48.7%, respectively. 2. The greatest number of one-year-old needle fascicle was found at 100% in RLI plot, whereas that of two-year-old needle fascicle appeared at 37% in RLI plot. The contribution rate of the light intensity to number of needle fascicle was 3.9% and factor of leaf age contributed to number of needle fascicle in 27.8%. The length of needles grown under different light intensities varied with needle ages. The longest length of new needles appeared at 37% in RLI plot, but old needles were not clear in influence of light intensity. The contribution rate to needle length by the light intensity was 2.5%. 3. The heaviest value of the fresh and dry weight of seedlings appeared at 100% of RLI plot then decreased with light intensity. The contribution rates to fresh and dry weight by the shading were 38% and 7.6% respectively. 4. The largest value of the dry weight of needles appeared at 100% of RLI plot and then decreased with light intensity. The contribution rates to dry weight of needles by the light intensity was 13.18%. 5. The values of T/R ratio increased with decreased light intensity and the contribution rate was 7.0%. 6. Positive correlation and linear regressions were recognized between dry weight of leaf and other factors (dry weight of shoot, root, seedling and diameter increment).

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.4
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• pp.347-370
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• 2011

Slurry type shield would be very effective for the tunnelling in a sandy ground, when the slurry pressure would be properly adjusted. Low slurry pressure could cause a tunnel face failure or a ground settlement in front of the tunnel face. Thus, the stability of tunnel face could be maintained by applying an excess slurry pressure that is larger than the active earth pressure. However, the slurry pressure should increase properly because an excessively high slurry pressure could cause the slurry flow out or the passive failure of the frontal ground. It is possible to apply the high slurry pressure without passive failure if a horizontal impermeable layer is located in the ground in front of the tunnel face, but its location, size, and effects are not clearly known yet. In this research, two-dimensional model tests were carried out in order to find out the effect of a horizontal impermeable layer for the slurry shield tunnelling in a saturated sandy ground. In tests slurry pressure was increased until the slurry flowed out of the ground surface or the ground fails. Location and dimension of the impermeable layer were varied. As results, the maximum and the excess slurry pressure in sandy ground were linearly proportional to the cover depth. Larger slurry pressure could be applied to increase the stability of the tunnel face when the impermeable layer was located in the ground above the crown in front of the tunnel face. The most effective length of the impermeable grouting layer was 1.0 ~ 1.5D, and the location was 1.0D above the crown level. The safety factor could be suggested as the ratio of the maximum slurry pressure to the active earth pressure at the tunnel face. It could also be suggested that the slurry pressure in the magnitude of 3.5 ~4.0 times larger than the active earth pressure at the initial tunnel face could be applied if the impermeable layer was constructed at the optimal location.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1024-1029
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• 2018

Purpose: We examined aqueous humor levels of 25-hydroxyvitamin D (vitamin D) in patients with age-related macular degeneration to investigate possible relationships between aqueous humor vitamin D levels and clinical manifestations. Methods: Patients > 50 years of age, 52 eyes of 34 patients with age-related macular degeneration, and 23 eyes of 17 patients treated with cataract surgery without retinal disease, were examined for aqueous humor vitamin D levels and compared. The experimental group was divided into two groups according to the median value of aqueous humor vitamin D levels. We compared the clinical manifestations of macular degeneration in both groups and identified relationships between aqueous humor vitamin D levels and clinical features. Results: Vitamin D levels in the aqueous humor were significantly lower in the experimental group than in the control group (experimental, $10.03{\pm}10.1ng/mL$ vs. control group, $40.8{\pm}16.4ng/mL$; p < 0.001). Patients with high vitamin D levels in the macular degeneration group had a higher percentage of fibrovascular pigment epithelial detachments than those in the low grade group (high grade group, 65% vs. low grade group, 27%; p = 0.003). Multiple linear regression analysis showed a significant correlation between vitamin D levels and the total number of anti-vascular endothelial growth factor intravitreal injections within 6 months (standardize coefficient, ${\beta}=-0.336$). Conclusions: Patients with wet age-related macular degeneration had significantly lower vitamin D levels in the aqueous humor compared to control group subjects of similar ages. However, in patients with macular degeneration, low vitamin D levels were associated with a greater number of intravitreal injections, while higher levels of vitamin D may lead to more advanced forms of fibrovascular retinal pigment epithelium and related low vision. These relationships were not always constant, so further studies on the relationships between local vitamin D levels and ocular disorders are needed.

• Journal of The Korean Ophthalmological Society
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• v.60 no.2
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• pp.144-151
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• 2019

Purpose: Intravitreal aflibercept, ranibizumab, bevacizumab, and dexamethasone are the most widely used drugs in the treatment of diabetic macular edema (DME). The aim of this study was to compare the efficacy and safety of anti-vascular endothelial growth factors and dexamethasone for the treatment of DME. Methods: There were nine previous systematic reviews on this topic; we updated these high-quality reviews. Seven studies were added to two studies following a literature search. Efficacy outcomes were 1) average improvement in visual acuity, 2) proportion of patients who experienced an improvement in vision (an increase in best-corrected visual acuity (BCVA) of ${\geq}15$ in the Early Treatment Diabetic Retinopathy Study [ETDRS]), and 3) proportion of patients who experienced worsening vision (a decrease in BCVA of ${\geq}15$ in the ETDRS). Safety outcomes included systemic adverse events and ocular-related adverse events. Results: The mean difference in the BCVA for ranibizumab versus bevacizumab treatment was 0.16 (95% confidence interval [CI]: -0.02, 0.34), and that for ranibizumab versus aflibercept was -0.08 (95% CI: -0.26, 0.10). The mean difference in the change of BCVA for aflibercept versus ranibizumab was -0.20 (95% CI: -0.40, -0.01), and that for aflibercept versus bevacizumab was -0.34 (95% CI: -0.53, -0.14). Other efficacy outcomes showed similar trends, and there was no significant difference between treatments. There was also no significant difference in both systemic and ocular adverse events rates between the treatments. Conclusions: In DME patients, the efficacy of aflibercept was found to be higher with respect to BCVA changes compared with ranibizumab or bevacizumab. However, there were no significant difference in terms of visual acuity improvement or visual acuity of more than 15 letters, nor in terms of anti-vascular endothelial growth factors (as a safety outcome).

• Korean Journal of Remote Sensing
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• v.23 no.6
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• pp.507-520
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• 2007

Satellite passive microwave(PM) sensors have been observing polar sea ice concentration(SIC), ice temperature, and snow depth since 1970s. Among them SIC is playing an important role in the various studies as it is considered the first factor for the monitoring of global climate and environment changes. Verification and correction of PM SIC is essential for this purpose. In this study, we calculated SIC from KOMPSAT-1 EOC images obtained from Arctic sea ice edges from July to August 2005 and compared with SSM/I SIC calculated from NASA Team(NT) algorithm. When we have no consideration of sea ice types, EOC and SSM/I NT SIC showed low correlation coefficient of 0.574. This is because there are differences in spatial resolution and observing time between two sensors, and the temporal and spatial variation of sea ice was high in summer Arctic ice edge. For the verification of SSM/I NT SIC according to sea ice types, we divided sea ice into land-fast ice, pack ice, and drift ice from EOC images, and compared them with SSM/I NT SIC corresponding to each ice type. The concentration of land-fast ice between EOC and SSM/I SIC were calculated very similarly to each other with the mean difference of 0.38%. This is because the temporal and spatial variation of land-fast ice is small, and the snow condition on the ice surface is relatively dry. In case of pack ice, there were lots of ice ridge and new ice that are known to be underestimated by NT algorithm. SSM/I NT SIC were lower than EOC SIC by 19.63% in average. In drift ice, SSM/I NT SIC showed 20.17% higher than EOC SIC in average. The sea ice with high concentration could be included inside the wide IFOV of SSM/I because the drift ice was located near the edge of pack ice. It is also suggested that SSM/I NT SIC overestimated the drift ice covered by wet snow.

• Journal of Legislation Research
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• no.44
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• pp.487-538
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• 2013

It is the most critical issue in recent international intellectual property licence disputes to decide the applicable laws to the license contracts. As Korea and the European Union(EU) reached free trade agreement(FTA), and the EU-Korea FTA entered into force on July 1, 2011, the FTA has boosted social, economic, cultural exchanges between the two. As a result of the increased transactions in those sectors, legal disputes are also expected to grow. This situation calls for extensive research and understanding of the choice of law principles applicable to international intellectual property license contracts in the EU. To decide the laws applicable to issues arising from international intellectual property license contracts disputes, the characterization of those issues is necessary for the purpose of applying private international law principles to them. In terms of characterization, intellectual property license contracts fall within contractual matters. In the EU, the primary rule of choice of law principles in contractual obligations is the Rome I Regulation. Because the choice of law rules, such as private international law principles, the Rome Convention(1980), and the Rome I Regulation, differ in the time of application, it is essential to clarify the time factor of related contracts. For example, the Rome I Regulation applies to contracts which were concluded as from December 17, 2009. Although party autonomy in international contracts disputes is generally allowed, if there is no choice of law agreement between the parties to the contracts, the objective test rule of private international law doctrine could be the best option. Following this doctrine, the Rome I Regulation Article 4, Paragraph 1 provides the governing law rules based on the types of contracts, but there is no room for intellectual property license contracts. After all, as the rule for governing law of those contracts, the Rome I Regulation Article 4, Paragraph 2 should be applied and if there are countries which are more closely connected to the contracts under the Rome I Regulation Article 4, Paragraph 3, the laws of those countries become the governing laws of the contracts. Nevertheless, if it is not possible to decide the applicable laws to the license contracts, the Rome I Regulation Article 4, Paragraph 4 should be applied in the last resort and the laws of the countries which are the most closely connected to the contracts govern the license contracts. Therefore, this research on the laws applicable to intellectual property license contracts under the Rome I Regulation suggests more systematic and effective solutions for future disputes in which Korea and the EU countries play the significant role as the connecting factors in the conflict of laws rules. Moreover, it helps to establish comprehensive and theoretical understanding of applying the Korean Private International Law to multifarious choice-of-law cases.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.286-292
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• 2019

This study aimed to investigate the suitable of layer on growth of six baby leaf vegetables using existing facilities and equipment in rice seedling nursery. Three kinds of Lactuca(lettuce 'Jinppallola' and 'Romain white', and indian lettuce), two of Brassica(tatsoi and red tatsoi) and amaranth were used as the materials. After sowing, the rice seedling tray was placed in multi bench system($L120{\times}W60{\times}H195cm$, 10th floor), which were low(1st) layer above 15cm, middle(4th) layer above 115cm and high(7th) layer above 175cm apart from ground. Irrigation was sprayed 2~3 times a day using a automatic irrigation system. The growth characteristics and leaf color were investigated when leaf vegetables were reached the optimum size(within 10cm of plant height). During the culture periods(29th Jun.~31th Jul. 2017), daytime average temperature was $27.4{\sim}28.3^{\circ}C$ regardless of layers but solar irradiance was higher in the high-layer than low and middle-layer of 37% and 22%, respectively. The leaf length, leaf width and number of leaves in middle and high-layer have a tendency to increase but, fresh weight was different according to the layer. When the correlation between accumulation radiation and growth was analyzed, all of growth factor of Amaranth showed a high correlation and other cultivars showed correlation with each growth factors. As a result, It is suitable that amaranth and red tatsoi for high-layer, Indian lettuce and tatsoi for middle and high-layer and 'Romain white' for middle-layer. The growth of red lettuce 'Jinppallola' was good at low layer, but leaf color expression was poor. So the high layer is suitable for 'Jinppallola'.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.2
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• pp.217-223
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• 1997

This study was performed to determine if women with day 3 serum inhibin-B concentrations <45pg/ml (conversion factor to SI unit, 1.00) demonstrate a poor response to ovulation induction and assisted reproductive technology outcome to women with inhibin-B${\ge}45pg$/ml, independant of day 3 FSH, E2 and patient age. From Jan 1996 to Dec 1996, 16 volunteers patients who underwent 25 IVF cycles with luteal phase GnRH agonist suppression and HMG stimulation were allocated to the study group. We evaluated day 3 serum inhibin-B, FSH, E2, peak E2, cancellation rate per initiated cycle (%) and clinical pregnancy rate per initiated cycle (%) according to the above two groups and independent of patient age, day 3 FSH, day 3 E2 and all of above combined. Women with day 3 serum inhibin-B${\ge}45pg$/ml demonstrated higher average day 3 inhibin-B level, clinical pregnancy rate per initiated cycle ($20.3{\pm}2.5$ pg/ml vs $80.9{\pm}5.0$ pg/ml, p<0.05; 24.8% vs 8.5%, p<0.05) and lower day 3 FSH level, cancellation rate per initiated cycle ($6.9{\pm}0.3$ mIU/ml vs $8.5{\pm}0.5$ mIU/ml, p<0.05; 1.5% vs 9.0%, p<0.05). Women with day 3 serum inhibin${\ge}45pg$/ml and age<40 year demonstrated higher pregnancy rate per initiated cycle (28.2% vs 7.4%, p<0.05) and lows. day 3 FSH level, cancellation rate per initiated cycle ($6.9{\pm}0.5$ mIU/ml vs $8.2{\pm}0.7$ mIU/ml, p<0.05; 1.0% vs 9.0%, p<0.05). Women with day 3 serum inhibin${\ge}45pg$/ml and day 3 FSH<15mIU/ml demonstrated higher pregnancy rate per initiated cycle (33.5% vs 9.5%, p<0.05) and lower day 3 FSH level, cancellation rate per initiated cycle ($7.7{\pm}0.2$ mIU/ml vs $8.5{\pm}0.5$ mIU/ml, p<0.05; 1.5% vs 10.0%, p<0.05). Women with day 3 serum inhibin${\ge}45pg$/ml and day 3 E2<50pg/ml demonstrated higher pregnancy rate per initiated cycle (30.0% vs 9.5%, p<0.05) and lower cancellation rate per initiated cycle (1.5% vs 9.5%, p<0.05). Women with day 3 serum inhibin${\ge}45pg$/ml, age<40 year, day 3 FSH<15mIU/ml and day 3 E2<50pg/ml demonstrated higher pregnancy rate per initiated cycle (30.0% vs 10.8%, p<0.05) and lower day 3 FSH level, cancellation rate per initiated cycle ($6.8{\pm}0.6$ mIU/ml vs $8.4{\pm}0.9$ mIU/ml, p<0.05; 1.5% vs 7.8%, p<0.05). Therefore women with low day 3 serum inhibin-B concentrations demonstrate a poorer response to ovulation induction and are less likely to conceive a clinical pregnancy though ART relative to women with high day 3 inhibin-B and day 3 serum inhibin-B, in addition to a day 3 FSH, E2 and patient age, appears helpful in prediction in IVF-ET outcome.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1234-1268
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• 2004

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2002 and 2003 has been carried out. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment/design. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation in diverse facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat transfer, humidity was also interesting to promote comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing research topics. Well developed CFD technologies were widely applied for analysis and design of various facilities and their systems. (2) Heat transfer characteristics of enhanced finned tube heat exchangers and heat sinks were extensively investigated. Experimental studies on the boiling heat transfer, vortex generators, fluidized bed heat exchangers, and frosting and defrosting characteristics were also conducted. In addition, the numerical simulations on various heat exchangers were performed and reported to show heat transfer characteristics and performance of the heat exchanger. (3) A review of the recent studies shows that the performance analysis of heat pump have been made by various simulations and experiments. Progresses have been made specifically on the multi-type heat pump systems and other heat pump systems in which exhaust energy is utilized. The performance characteristics of heat pipe have been studied numerically and experimentally, which proves the validity of the developed simulation programs. The effect of various factors on the heat pipe performance has also been examined. Studies of the ice storage system have been focused on the operational characteristics of the system and on the basics of thermal storage materials. Researches into the phase change have been carried out steadily. Several papers deal with the cycle analysis of a few thermodynamic systems which are very useful in the field of air-conditioning and refrigeration. (4) Recent studies on refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement when new alternative refrigerants are applied. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and new alternative refrigerants including natural refrigerants. Efficiency of various compressors and performance of new expansion devices are also dealt with for better design of refrigeration/air conditioning system. In addition to the studies related with thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out. It should be noted that the researches on two-phase flow are constantly carried out. (5) A review of the recent studies on absorption refrigeration system indicates that heat and mass transfer enhancement is the key factor in improving the system performance. Various experiments have been carried out and diverse simulation models have been presented. Study on the small scale absorption refrigeration system draws a new attention. Cooling tower was also the research object in the respect of enhancement its efficiency, and performance analysis and optimization was carried out. (6) Based on a review of recent studies on indoor thermal environment and building service systems, it is noticed that research issues have mainly focused on several innovative systems such as personal environmental modules, air-barrier type perimeterless system with UFAC, radiant floor cooling system, etc. New approaches are highlighted for improving indoor environmental conditions and minimizing energy consumption, various activities of building energy management and cost-benefit analysis for economic evaluation.