• Title/Summary/Keyword: Factor Structure

Search Result 5,214, Processing Time 0.041 seconds

The Relationship between Internet Search Volumes and Stock Price Changes: An Empirical Study on KOSDAQ Market (개별 기업에 대한 인터넷 검색량과 주가변동성의 관계: 국내 코스닥시장에서의 산업별 실증분석)

  • Jeon, Saemi;Chung, Yeojin;Lee, Dongyoup
    • Journal of Intelligence and Information Systems
    • /
    • v.22 no.2
    • /
    • pp.81-96
    • /
    • 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.

Earthquake impacts on hydrology: a case study from the Canterbury, New Zealand earthquakes of 2010 and 2011

  • Davie, Tim;Smith, Jeff;Scott, David;Ezzy, Tim;Cox, Simon;Rutter, Helen
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2011.05a
    • /
    • pp.8-9
    • /
    • 2011
  • On 4 September 2010 an earthquake of magnitude 7.1 on the Richter scale occurred on the Canterbury Plains in the South Island of New Zealand. The Canterbury Plains are an area of extensive groundwater and spring fed surface water systems. Since the September earthquake there have been several thousand aftershocks (Fig. 1), the largest being a 6.3 magnitude quake which occurred close to the centre of Christchurch on 22February 2011. This second quake caused extensive damage to the city of Christchurch including the deaths of 189 people. Both of these quakes had marked hydrological impacts. Water is a vital natural resource for Canterburywith groundwater being extracted for potable supply and both ground and surface water being used extensively for agricultural and horticultural irrigation.The groundwater is of very high quality so that the city of Christchurch (population approx. 400,000) supplies untreated artesian water to the majority of households and businesses. Both earthquakes caused immediate hydrological effects, the most dramatic of which was the liquefaction of sediments and the release of shallow groundwater containing a fine grey silt-sand material. The liquefaction that occurred fitted within the empirical relationship between distance from epicentre and magnitude of quake described by Montgomery et al. (2003). . It appears that liquefaction resulted in development of discontinuities in confining layers. In some cases these appear to have been maintained by artesian pressure and continuing flow, and the springs are continuing to flow even now. In spring-fed streams there was an increase in flow that lasted for several days and in some cases flows remained high for several months afterwards although this could be linked to a very wet winter prior to the September earthquake. Analysis of the slope of baseflow recession for a spring-fed stream before and after the September earthquake shows no change, indicating no substantial change in the aquifer structure that feeds this stream.A complicating factor for consideration of river flows was that in some places the liquefaction of shallow sediments led to lateral spreading of river banks. The lateral spread lessened the channel cross section so water levels rose although the flow might not have risen accordingly. Groundwater level peaks moved both up and down, depending on the location of wells. Groundwater level changes for the two earthquakes were strongly related to the proximity to the epicentre. The February 2011 earthquake resulted in significantly larger groundwater level changes in eastern Christchurch than occurred in September 2010. In a well of similar distance from both epicentres the two events resulted in a similar sized increase in water level but the slightly slower rate of increase and the markedly slower recession recorded in the February event suggests that the well may have been partially blocked by sediment flowing into the well at depth. The effects of the February earthquake were more localised and in the area to the west of Christchurch it was the earlier earthquake that had greater impact. Many of the recorded responses have been compromised, or complicated, by damage or clogging and further inspections will need to be carried out to allow a more definitive interpretation. Nevertheless, it is reasonable to provisionally conclude that there is no clear evidence of significant change in aquifer pressures or properties. The different response of groundwater to earthquakes across the Canterbury Plains is the subject of a new research project about to start that uses the information to improve groundwater characterisation for the region. Montgomery D.R., Greenberg H.M., Smith D.T. (2003) Stream flow response to the Nisqually earthquake. Earth & Planetary Science Letters 209 19-28.

  • PDF

A study on the level of codependency among social work related professionals and its effect on their burnout: Focusing on moderating effects of Sex-role attitude (사회복지종사자의 공동의존성과 소진에 관한 연구 : 성역할태도의 조절효과를 중심으로)

  • Jang, Gyeongho;Yoon, Kyeonga;Shim, Woochan
    • Korean Journal of Social Welfare Studies
    • /
    • v.47 no.1
    • /
    • pp.29-56
    • /
    • 2016
  • The purpose of this study is first, to explore the level of codependency among social work related professionals since codependency of professionals in the field has not been explored much in Korea. Second purpose is to examine whether codependency affects the level of burnout. Last purpose is to examine moderating effects of the Sex-role attitude on the relationship between codependency and burnout. Data were collected from the 11th of December in 2014 until the 28th of February in the following year. Self-administered questionnaires were distributed to care professionals practicing in social work institutions in Daejeon City and Choongcheong province, via email and mail. In addition, surveys were administered at several continuing education training venues. Instruments used for this study include CODAT(Codependency Assessment Tool) developed by Hughes-Hammer and colleagues in 1998, MBI(Maslach Burnout Inventory) developed by Maslach and Jackson in 1981, and SRA(Sex Role Attitude) developed by Osmond and Maryin in 1975. In total, 368 surveys were used for final analysis. The results include that gender did not have statistically significant relationship with the overall codependency, however, male showed statistically higher score than female in one of subscales of codependency called hiding oneself. Workers in the residential settings showed higher level of codependency than those in non-residential settings, especially in the subscale of Other focus or Self-neglect. Codependency showed a strong relationship with Burnout. Among the five-factor structure of the CODAT, Medical problem, Low Self-worth and Family of Origin showed strong relationship with the Burnout score. And the moderating effects of Sex-role Attitude showed a statistically significant relationship between codependency and burnout. Conservative sex-role attitude amplified the level of burnout on the relationship between codependency and burnout. Based on the result, educational and policy implications were made in order to prevent burnout among social work related professionals.

A Comparative Study on Resident and Tourist Value Systems of the Ancient Tombs in Gyeong-ju City Center - A Focus on Means-End Chain - (경주 도심 고분에 대한 지역주민과 관광객의 가치체계 비교연구 - 수단-목적 사슬 이론을 중심으로 -)

  • Seok, Mi-Jeong;Park, Joung-Koo;Kang, Tai-Ho
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.47 no.2
    • /
    • pp.88-99
    • /
    • 2019
  • This study aims to conduct a depth analysis of motivation and value of local residents and tourists based on means-end chain theory. The sampling of the study was conducted on local residents living near downtown area of Gyeong-ju City, and tourists through soft laddering and hard laddering methods. A mutual correlation model in relation with Hierarchical Value Map (HVM) for each group by conducting the analysis of factor loading (attributes, consequences, value) and cognitive structure (the correlations among attributes, consequences and value) was proposed and the comparisons of HVM for each group was also conducted. The structured questionnaires using Association Pattern Technique (APT) of hard laddering were utilized to analyze the means and end of value chain structures in terms of the attributes, consequences, value of Gyeong-ju Ancient Tombs. The findings propose that local residents are visiting Ancient Tombs Gyeong-ju City Center for 'Rest and take a walk' as the means, which results in 'Relieving stress' and eventually leads to the 'Improvement of historic and cultural cultivation' as the end. On the other hand, tourists also 'Rest and take a walk' as the mean, which also leads to 'Relieving stress'. However, unlike local residents, it eventually leads to 'Self-reflection and healing' as the end. It is expected that the findings of this study not only recommend us to consider preserving and managing cultural heritages and value of ancient tombs in developing "Ancient Tomb Park in Gyoneg-ju City Center" but also provides baseline data for the establishment of reasonable plans of utilizing tombs, historical and cultural heritages.

Archival Appraisal of Public Records Regarding Urban Planning in Japanese Colonial Period (조선총독부 공문서의 기록학적 평가 -조선총독부 도시계획 관련 공문서군을 중심으로-)

  • Lee, Seung Il
    • The Korean Journal of Archival Studies
    • /
    • no.12
    • /
    • pp.179-235
    • /
    • 2005
  • In this article, the task of evaluating the official documents that were created and issued by the Joseon Governor General office during the Japanese occupation period, with new perspectives based upon the Macro-Appraisal approaches developed by the Canadian scholars and personnel, will be attempted. Recently, the Canadian people and the authorities have been showing a tendency of evaluating the meaning and importance of a particular document with perspectives considering the historical situation and background conditions that gave birth to that document to be a more important factor, even than considering the quality and condition of that very document. Such approach requires the archivists to determine whether they should preserve a certain document or not based upon the meaning, functions and status of the entity that produced the document or the meaning of the documentation practice itself, rather than the actual document. With regard to the task of evaluating the official documents created and issued by the Joseon Governor General office and involved the city plans devised by the office back then, this author established total of 4 primary tasks that would prove crucial in the process of determining whether or not a particular theme, or event, or an ideology should be selected and documents involving those themes, events and ideologies should be preserved as important sources of information regarding the Korean history of the Japanese occupation period. Those four tasks are as follow: First, the archivists should study the current and past trends of historical researches. The archivists, who are usually not in the position of having comprehensive access to historical details, must consult the historians' studies and also the trends mirrored in such studies, in their efforts of selecting important historical events and themes. Second, the archivists should determine the level of importance of the officials who worked inside the Joseon Governor General office as they were the entities that produced the very documents. It is only natural to assume that the level of importance of a particular document must have been determined by the level of importance(in terms of official functions) of the official who authorized the document and ordered it to be released. Third, the archivists should be made well aware of the inner structure and official functions of the Joseon Governor General office, so that they can have more appropriate analyses. Fourth, in order to collect historically important documents that involved the Koreans(the Joseon people), the archivists should analyze not only the functions of the Joseon Governor General office in general but also certain areas of the Office's business in which the Japanese officials and the Koreans would have interacted with each other. The act of analyzing the documents only based upon their respective levels of apparent importance might lead the archivists to miss certain documents that reflected the Koreans' situation or were related to the general interest of the Korean people. This kind of evaluation should provide data that are required in appraising how well the Joseon Governor General office's function of devising city plans were documented back then, and how well they are preserved today, utilizing a comparative study involving the Joseon Governor General office's own evaluations of its documentations and the current status of documents that are in custody of the National Archive. The task would also end up proposing a specialized strategy of collecting data and documents that is direly needed in establishing a well-designed comprehensive archives. We should establish a plan regarding certain documents that were documented by the Joseon Governor General office but do not remain today, and devise a task model for the job of primary collecting that would take place in the future.

Effect of micro-environment in ridge and southern slope on soil respiration in Quercus mongolica forest

  • Lee, Jae-Seok
    • Journal of Ecology and Environment
    • /
    • v.42 no.4
    • /
    • pp.210-218
    • /
    • 2018
  • Background: Soil respiration (Rs) is a major factor of the absorption and accumulation of carbon through photosynthesis in the ecosystem carbon cycle. This directly affects the amount of net ecosystem productivity, which affects the stability and sustainability of the ecosystem. Understanding the characteristics of Rs is indispensable to scientifically understand the carbon cycle of ecosystems. It is very important to study Rs characteristics through analysis of environmental factors closely related to Rs. Rs is affected by various environmental factors, such as temperature, precipitation, soil moisture, litter supply, organic matter content, dominant plant species, and soil disturbance. This study was conducted to analyze the effects of micro-topographical differences on Rs in forest vegetation by measuring the Rs on the ridge and southern slope sites of the broadly established Quercus mongolica forest in the central Korean area. Method: Rs, Ts, and soil moisture data were collected at the southern slope and ridge of the Q. mongolica forest in the Mt. Jeombong area in order to investigate the effects of topographical differences on Rs. Rs was collected by the closed chamber method, and data collection was performed from May 2011 to October 2013, except Winter seasons from November to April or May. For collecting the raw data of Rs in the field, acrylic collars were placed at the ridge and southern slope of the forest. The accumulated surface litter and the soil organic matter content (SOMC) were measured to a 5 cm depth. Based on these data, the Rs characteristics of the slope and ridge were analyzed. Results: Rs showed a distinct seasonal variation pattern in both the ridge and southern slope sites. In addition, Rs showed a distinct seasonal variation with high and low Ts changes. The average Rs measurements for the two sites, except for the Winter periods that were not measured, were $550.1\;mg\;CO_2m^{-2}h^{-1}$ at the ridge site and $289.4\;mg\;CO_2m^{-2}h^{-1}$ at the southern slope, a difference of 52.6%. There was no significant difference in the Rs difference between slopes except for the first half of 2013, and both sites showed a tendency to increase exponentially as Ts increased. In addition, although the correlation is low, the difference in Rs between sites tended to increase as Ts increased. SMC showed a large fluctuation at the southern slope site relative to the ridge site, as while it was very low in 2013, it was high in 2011 and 2012. The accumulated litter of the soil surface and the SOMC at the depth range of 0~5 cm were $874g\;m^{-2}$ and 23.3% at the ridge site, and $396g\;m^{-2}$ and 19.9% at the southern slope site. Conclusions: In this study, Rs was measured for the ridge and southern slope sites, which have two different results where the surface litter layer is disturbed by strong winds. The southern slope site shows that the litter layer formed in autumn due to strong winds almost disappeared, and while in the ridge site, it became thick due to the transfer of litter from the southern slope site. The mean Rs was about two times higher in the ridge site compared to that in the southern slope site. The Rs difference seems to be due to the difference in the amount of litter accumulated on the soil surface. As a result, the litter layer supplied to the soil surface is disturbed due to the micro-topographical difference, as the slope and the change of the community structure due to the plant season cause heterogeneity of the litter layer development, which in turn affects SMC and Rs. Therefore, it is necessary to introduce and understand these micro-topographical features and mechanisms when quantifying and analyzing the Rs of an ecosystem.

Molecular Characterization and Expression Analysis of Clathrin-Associated Adaptor Protein 3-δ Subunit 2 (AP3S2) in Chicken

  • Oh, Jae-Don;Bigirwa, Godfrey;Lee, Seokhyun;Song, Ki-Duk
    • Korean Journal of Poultry Science
    • /
    • v.46 no.1
    • /
    • pp.31-37
    • /
    • 2019
  • A chicken clathrin-associated adaptor protein $3-{\delta}$ subunit 2 (AP3S2) is a subunit of AP3, which is involved in cargo protein trafficking to target membrane with clathrin-coated vesicles. AP3S2 may play a role in virus entry into host cells through clathrin-dependent endocytosis. AP3S2 is also known to participate in metabolic disease developments of progressions, such as liver fibrosis with hepatitis C virus infection and type 2 diabetes mellitus. Chicken AP3S2 (chAP3S2) gene was originally identified as one of the differentially expressed genes (DEGs) in chicken kidney which was fed with different calcium doses. This study aims to characterize the molecular characteristics, gene expression patterns, and transcriptional regulation of chAP3S2 in response to the stimulation of Toll-like receptor 3 (TLR3) to understand the involvement of chAP3S2 in metabolic disease in chicken. As a result, the structure prediction of chAP3S2 gene revealed that the gene is highly conserved among AP3S2 orthologs from other species. Evolutionarily, it was suggested that chAP3S2 is relatively closely related to zebrafish, and fairly far from mammal AP3S2. The transcriptional profile revealed that chAP3S2 gene was highly expressed in chicken lung and spleen tissues, and under the stimulation of poly (I:C), the chAP3S2 expression was down-regulated in DF-1 cells (P<0.05). However, the presence of the transcriptional inhibitors, BAY 11-7085 (Bay) as an inhibitor for nuclear factor ${\kappa}B$ ($NF{\kappa}B$) or Tanshinone IIA (Tan-II) as an inhibitor for activated protein 1 (AP-1), did not affect the expressional level of chAP3S2, suggesting that these transcription factors might be dispensable for TLR3 mediated repression. These results suggest that chAP3S2 gene may play a significant role against viral infection and be involved in TLR3 signaling pathway. Further study about the transcriptional regulation of chAP3S2 in TLR3 pathways and the mechanism of chAP3S2 upon virus entry shall be needed.

Performance assessment of an urban stormwater infiltration trench considering facility maintenance (침투도랑 유지관리를 통한 도시 강우유출수 처리 성능 평가)

  • Reyes, N.J. D.G.;Geronimo, F.K.F.;Choi, H.S.;Kim, L.H.
    • Journal of Wetlands Research
    • /
    • v.20 no.4
    • /
    • pp.424-431
    • /
    • 2018
  • Stormwater runoff containing considerable amounts of pollutants such as particulates, organics, nutrients, and heavy metals contaminate natural bodies of water. At present, best management practices (BMP) intended to reduce the volume and treat pollutants from stormwater runoff were devised to serve as cost-effective measures of stormwater management. However, improper design and lack of proper maintenance can lead to degradation of the facility, making it unable to perform its intended function. This study evaluated an infiltration trench (IT) that went through a series of maintenance operations. 41 monitored rainfall events from 2009 to 2016 were used to evaluate the pollutant removal capabilities of the IT. Assessment of the water quality and hydrological data revealed that the inflow volume was the most relative factor affecting the unit pollutant loads (UPL) entering the facility. Seasonal variations also affected the pollutant removal capabilities of the IT. During the summer season, the increased rainfall depths and runoff volumes diminished the pollutant removal efficiency (RE) of the facility due to increased volumes that washed off larger pollutant loads and caused the IT to overflow. Moreover, the system also exhibited reduced pollutant RE for the winter season due to frozen media layers and chemical-related mechanisms impacted by the low winter temperature. Maintenance operations also posed considerable effects of the performance of the IT. During the first two years of operation, the IT exhibited a decrease in pollutant RE due to aging and lack of proper maintenance. However, some events also showed reduced pollutant RE succeeding the maintenance as a result of disturbed sediments that were not removed from the geotextile. Ultimately, the presented effects of maintenance operations in relation to the pollutant RE of the system may lead to the optimization of maintenance schedules and procedures for BMP of same structure.

Effect of Prostaglandin F2 Alpha on E-cadherin, N-cadherin and Cell Adhesion in Ovarian Luteal Theca Cells (난소의 황체협막세포에서 E-cadherin, N-cadherin과 세포부착에 미치는 Prostaglandin F2 Alpha의 영향)

  • Lee, Sang-Hee;Jung, Bae Dong;Lee, Seunghyung
    • Korean Journal of Clinical Laboratory Science
    • /
    • v.51 no.3
    • /
    • pp.360-369
    • /
    • 2019
  • Cadherins are essential transmembrane proteins that promote cell-cell adhesion and maintain the corpus luteum structure in the ovary. This study examined the influence of prostaglandin F2 alpha ($PGF2{\alpha}$) on E-cadherin, N-cadherin, and adhesion in luteal theca cells (LTCs). The luteal cells were isolated from the mid-phase corpus luteum, and the LTCs were cultured separately from the luteal heterogeneous cells according to the morphology of the mesenchymal cells and to determine if steroidogenic and endothelial cells of LTCs, 3beta-hydroxysteroid dehydrogenase ($3{\beta}$-HSD), and vascular endothelial growth factor receptor 2 (VEGFR2) mRNA were used. The LTCs were then incubated in the culture medium supplemented with 0.01, 0.1, and 1.0 mM $PGF2{\alpha}$ for 24 h, and the E-cadherin and N-cadherin proteins in the LTCs were detected by confocal laser scanning microscopy. The results revealed $3{\beta}$-HSD mRNA expression in the LTC but no VEGF2R mRNA expression. The E-cadherin and N-cadherin proteins of the LTCs were damaged in the 0.01, 0.1, and 1.0 mM $PGF2{\alpha}$ treatment groups, and the expression of the N-cadherin protein was reduced significantly in 0.01 mM $PGF2{\alpha}$ compared to the 0 mM $PGF2{\alpha}$ treatment groups (P<0.05). In addition, the number of attached LTCs were significantly lower in the 0.01 mM $PGF2{\alpha}$ treatment group than in the 0 mM $PGF2{\alpha}$ treatment group (P<0.05). In conclusion, $PGF2{\alpha}$ affected the disruption of cadherin proteins and cell adhesion in LTCs. These results may help better understand the cadherin and adhesion mechanism during corpus luteum regression in the ovary.

A study on the variant placement method of the traditional wooden architecture, rafter (전통 목조건축 서까래의 이형적(異形的) 배치 방식 연구)

  • Hong, Eun-ki;Chang, Hun-duck
    • Korean Journal of Heritage: History & Science
    • /
    • v.48 no.4
    • /
    • pp.110-125
    • /
    • 2015
  • This study is objected to investigate the repairing method and the modification period of rafters via the transformation traces left in the superciliums, where repair process takes places frequently. This is the basic research of analyzing the architectural features of Deokkeori, one of the additional-rafter methods. Deokkeori method can be described as using Deokdori in the top section of Hayeon, and placement of Sangyeon above it. This method was started to be used since middle of the Joseon dynasty period(middle 18th Century) and mainly used at 19th Century to resist the transformation caused by repairing. It had been gradually developed from non-application stage to application stage including additional usage of complement. The architectural features of Deokkeori can be categorized into four. First, the usage of Deokdori to connect Sangyeon to the top section of Hayeon. It reduct the direct connection between Sangyoen and Hayeon, therefore give constructive benefits and prevent the downfall of the eaves by increasing the power which pressing the top section of Hayeon. Second, it gives the autonomy to the inside structure of ceiling by comprising it. By using Deokdori, the limit of top section's longitude was eliminated while also simplify the upper section by blocking the inside structures with ceiling. In addition, the complements occasionally seen in several buildings increase the power which pressing Hayeon. Third, the ceiling's slope has been changed to be concerned with Sangyeon, instead of Hayeon which was highly related with it before. The last factor is the thickness of rafters which used in Deokkeori. The diameter is thiner in Sangyeon than Hayeon.