• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.76.1-76.1
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• 2019

CTA 102, one of gamma-ray bright active galactic nuclei (AGN) has been observed with Korean very long baseline interferometry (VLBI) network (KVN) during the period of 2012 December-2018 May as part of interferometric Monitoring Of Gamma-ray Bright AGN (iMOGABA). Multi-frequency VLBI observations enable us to compare the milliarcsecond(mas)-scale iMOGABA images of relativistic jets with those from the Monitoring Of Jets in AGN with Very long baseline array (VLBA) Experiments (MOJAVE) and the VLBA-Boston University(BU)-BLAZAR programs which use VLBA with its angular resolutions of 0.2-1.3 mas. In spite of the relative larger beam sizes of KVN (1-10 mas), we are able to identify jet components of CTA 102 using the KVN multi-frequency VLBI observations with those resolved with VLBA. Considering an instrumental beam blending effect on the jet component identification, we were able to obtain a blending shift of the core position based on a convolution analysis using the VLBA data. When we apply the core position shift to the KVN images of CTA 102, we find that the identified jet components of CTA 102 from the KVN observations are well matched with those from the VLBA observations. Based on the results of the analysis, we may be able to study the jet kinematics and its correlation with gamma-ray flare activity.

• Journal of Distribution Science
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• v.14 no.1
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• pp.93-102
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• 2016

Purpose - The purpose of paper is studying the static and dynamic side for long-term memory storage properties, and increase the explanatory power regarding the long-term memory process by looking at the long-term storage attributes, Korea Composite Stock Price Index. The reason for the use of GPH statistic is to derive the modified statistic Korea's stock market, and to research a process of long-term memory. Research design, data, and methodology - Level shifts were subjected to be an empirical analysis by applying the GPH method. It has been modified by taking into account the daily log return of the Korea Composite Stock Price Index a. The Data, used for the stock market to analyze whether deciding the action by the long-term memory process, yield daily stock price index of the Korea Composite Stock Price Index and the rate of return a log. The studies were proceeded with long-term memory and long-term semiparametric method in deriving the long-term memory estimators. Chapter 2 examines the leading research, and Chapter 3 describes the long-term memory processes and estimation methods. GPH statistics induced modifications of statistics and discussed Whittle statistic. Chapter 4 used Korea Composite Stock Price Index to estimate the long-term memory process parameters. Chapter 6 presents the conclusions and implications. Results - If the price of the time series is generated by the abnormal process, it may be located in long-term memory by a time series. However, test results by price fixed GPH method is not followed by long-term memory process or fractional differential process. In the case of the time-series level shift, the present test method for a long-term memory processes has a considerable amount of bias, and there exists a structural change in the stock distribution market. This structural change has implications in level shift. Stratum level shift assays are not considered as shifted strata. They exist distinctly in the stock secondary market as bias, and are presented in the test statistic of non-long-term memory process. It also generates an error as a long-term memory that could lead to false results. Conclusions - Changes in long-term memory characteristics associated with level shift present the following two suggestions. One, if any impact outside is flowed for a long period of time, we can know that the long-term memory processes have characteristic of the average return gradually. When the investor makes an investment, the same reasoning applies to him in the light of the characteristics of the long-term memory. It is suggested that when investors make decisions on investment, it is necessary to consider the characters of the long-term storage in reference with causing investors to increase the uncertainty and potential. The other one is the thing which must be considered variously according to time-series. The research for price-earnings ratio and investment risk should be composed of the long-term memory characters, and it would have more predictability.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.4
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• pp.389-397
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• 2010

Purpose: This study was to investigate the changes of refractive error and astigmatism associated with age in Korean subjects between the ages of 6 and 80 years during 10-year period. Methods: 220 normal subjects (345 eyes) who visited ophthalmic clinic was recruited and followed for 10 years between 1999 and 2009, cycloplegic manifest refraction being performed annually. Visual acuity was tested on a Han's chart. Results: The mean 10-year change in the spherical equivalent refraction (SER) of age 6 to 10 years old and 10 to 20 years was -3.649D and -2.165D respectively. There was no change of refractive error in age 21 to 40 years. The myopic shift decreased with age from 41 up to 69 years but increased slightly in patients 70 years and older; the hyperopic shift showed the opposite trend. The distribution of refractive error over the 10 years in aged 6 to 10 and 11 to 20 years was shifted myopic. The incidence of medium (> -3.01D) to high myopia at age 6 to 10 years was 4.8% and after 10 years was 62.5%. The 10-year change of astigmatism axis was in "with the rule" direction for younger age group and in a "against the rule" direction for older subjects. Conclusions: This study has documented refractive error changes in Korean subjects and confirmed reported trends of myopic shift from age 6-20 years and hyperopic shift before age 70 years and a myopic shift thereafter. The axis of astigmatism turns to "against the rule" after 40's.

• Journal of Oral Medicine and Pain
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• v.26 no.1
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• pp.75-85
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• 2001

This study was performed to investigate the effect of mandibular midline shift and difference of mandibular height between both sides on the electromyo- graphic(EMG) activity of the masticatory muscles on clenching or gum chewing movement. For this study, 105 patients with temporomandibular disorders(TMD) were selected and panoramic radiograph were taken. Amount and side of the midline shift and height of the mandible from antegonial notch to the top of the condylar head were measured on panoramic view. $BioEMG^{(R)}$ (Bioresearch Inc., Milwaukee, USA) was used for recording of EMG activity(${\mu}V$) of the anterior temporalis and the superficial masseter on clenching or gum chewing movement. EMG activity on clenching during 533msec period were measured for activity of the starting point and the one second-after activity as the early EMG and the maximum EMG, respectively. EMG activity on gum chewing movement were measured for activity of the first and the second chewing stroke. The data collected were analysed by SPSS windows program, and the results of this study were as follows : 1. Height of the mandible was 8.06cm on right side and 8.03cm on left side, and showed no difference by age, but significantly differed by sex with higher in male subjects. 2. Mean value of the midline shift was 0.1mm with range of 0~5mm on both sides. The amount and side of the midline shift did not related with height difference of the mandible and/or the EMG activity of the masticatory muscles on clenching. 3. Prevalence of higher right side and higher left side of the mandible were almost same, and the EMG activity of higher side was not higher than that of the other side. 4. In the subjects with height difference of more than 5mm between both sides of the mandible, the early EMG activity on clenching were differed for the anterior temporalis, but the maximum activity were differed for the superficial masseter. 5. In the subjects with height difference of more than 5mm between both sides of the mandible, EMG activity of the anterior temporalis of the gum chewing side was not higher than that of the other side when chewing on the side of lower height, but in the subjects with height difference of less than 5mm, the EMG activity was higher than that of the other side.

• Journal of Ecology and Environment
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• v.35 no.1
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• pp.15-25
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• 2012

Time series of ocean climate indices and catch records were used to identify the alternation patterns of pelagic fish populations in relation to climate regime shifts. During 1910-2008, an orderly alternation of dominant pelagic fish groups was observed in the Tsushima Warm Current (TWC; Yellow Sea-East China Sea-East Sea/Japan Sea) and Kuroshio-Oyashio Current (KOC; Northwestern Pacific) regions. After the collapse of herring fishery in the late 1920s, the sardine (A group) dominated in the 1930s, 3 other species (C group; Pacific saury, jack mackerel, and anchovy) dominated in the 1950s-1960s, chub mackerel (B group) dominated in the 1970s, and then sardine (A group) dominated again during cool regime in the 1980s. As sardine biomass decreased in association with the climate regime shift that occurred in the late 1980s, catches of C group immediately increased after the regime shift and remained at high levels during warm regime in the 1990s. Alternations of dominant fish groups occurred 6 times between 1910 and 2008. The dominant period of the 7 species lasted for 10-20 years. The catch of Pacific sardine in the TWC and KOC regions showed a negative correlation with the catch of the other 5 species (Pacific herring, anchovy, jack mackerel, Pacific saury, and common squid), suggesting that the abundance of the 5 species is strongly affected by the abundance of Pacific sardine in relation to the climate regime shifts. The total catch level of the 7 species in the KOC region was generally higher than that in the TWC region before 1991 but was lower after 1992, suggesting that the fish populations in the Pacific side are shifted to the TWC region by zonal oscillation of the oceanic conditions in relation to the climate regime shift in the late 1980s.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.3
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• pp.280-288
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• 2016

Greenhouse gas (GHG) emissions have given rise to climate change which is one of the most serious environmental challenges that the world faces today. In response, Republic of Korea has proposed "Low Carbon, Green Growth" as a new economic paradigm accompanying with the ultimate aim of building a sense of responsibility for the environment. Korean government has set the ambitious national GHG emission reduction target which aims 37% reduction in the business-as-usual (BAU) level of 2030. The transportation sector plays a key role in this target. In the transportation sector, the GHG reduction target of 34.3% in the BAU level by 2020 has been allocated in order to consider the industrial specificity. Furthermore, it is known that the GHG reduction in the transportation sector has relatively minimal side effects compared to those of other sectors. In order to meet this national GHG reduction target, Korean government has set $CO_2$ emission regulation of vehicle for 2020. The purpose of this study is to evaluate the reduction effects by the average GHG regulation of vehicles. $CO_2$ emissions, between 2009 and 2013 were analysed by reduction measure such as technology improvement, light-weight, segment shift, diesel vehicle sales. During this period, $CO_2$ of vehicle was reduced every year by 19.9 g/km (i.e., 3.3% reduction per year). $CO_2$ reduction of imported vehicle is greater than domestic vehicle because of segment shift toward small size vehicle and higher diesel vehicle sales.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.730-737
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• 2017

Objective : Postoperative hydrocephalus is a common complication following craniectomy in patients with traumatic brain injury, and affects patients' long-term outcomes. This study aimed to verify the risk factors associated with the development of hydrocephalus after craniectomy in patients with acute traumatic subdural hemorrhage (tSDH). Methods : Patients with acute traumatic SDH who had received a craniectomy between December 2005 and January 2016 were retrospectively assessed by reviewing the coexistence of other types of hemorrahges, measurable variables on computed tomography (CT) scans, and the development of hydrocephalus during the follow-up period. Results : Data from a total of 63 patients who underwent unilateral craniectomy were analyzed. Postoperative hydrocephalus was identified in 34 patients (54%) via brain CT scans. Preoperative intraventricular hemorrhage (IVH) was associated with the development of hydrocephalus. Furthermore, the thickness of SDH (p=0.006) and the extent of midline shift before craniectomy (p=0.001) were significantly larger in patients with postoperative hydrocephalus. Indeed, multivariate analyses showed that the thickness of SDH (p=0.019), the extent of midline shift (p<0.001) and the coexistence of IVH (p=0.012) were significant risk factors for the development of postoperative hydrocephalus. However, the distance from the midline to the craniectomy margin was not an associated risk factor for postoperative hydrocephalus. Conclusion : In patients with acute traumatic SDH with coexisting IVH, a large amount of SDH, and a larger midline shift, close follow-up is necessary for the early prediction of postoperative hydrocephalus. Furthermore, craniectomy margin need not be limited in acute traumatic SDH patients for the reason of postoperative hydrocephalus.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.145-151
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• 2016

Temperature variability at the upper layer related to climate regime shifts in the Korean waters was illustrated using water temperature, climate index. Three major climate regime shifts (CRS) in 1976, 1988 and 1998 in north Pacific region had an significant influence on the major marine ecosystems structure pattern. Three marginal seas around Korean peninsula; East Sea, East China Sea and Yellow Sea also got important impact from this kind of decadal shift. We used 10m sea water temperatures in four regions of Korean waters since 1950 to detect major fluctuation patterns both seasonally and also decadal shift. 1988 CRS was occurred in all of the study areas in most seasons however, 1998 CRS was only detected in the Yellow Sea and in the southern part of the East Sea. 1976 CRS was detected in all of the study area mainly in winter. After 1998 CRS, the water temperature in the southern part of the East Sea, East China Sea and Yellow Sea were going into decreased pattern; however, in the northern part of the East Sea, it was further shifted to increasing pattern which was started from 1988 CRS period.

• 기호학연구
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• no.57
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• pp.27-57
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• 2018

This paper aims at (re)investigating the interrelationship between Communism and language in terms of historical experiences of Soviet Union in $20^{th}$ century. Critically reviewing Boris Groy's famous thesis about Soviet communism as the "kingdom of language", in which Soviet system is regarded as the result of "linguistic turn, executed in the dimension of social practice", i.e., as a state of "total linguistification of society", I will examine it in comparison with another very interesting view on the language system of communism(socialism): Alexie Yurchak's controversial thesis on "performative shift" in late socialism. Yurchak's unique view on Soviet socialism as a specific discourse system, thoroughly illuminating peculiar paradox of Soviet discourse system in the period of late socialism, in which performative repetition of authoritative ideological discourses does not prohibit, but rather enable the possibility of creative deviation from or unexpected reappropriation of them, could provide us with profound insights on the problematics around the collapse (the end) of "linguistic imperial" of Soviet Union.

• International Area Studies Review
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• v.13 no.3
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• pp.145-161
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• 2009

Applying the shift-share analysis, this paper decomposes FDI inflow into Korea for the period of 2003-2006. The paper finds that Korea has been lagging behind the world average in absorbing inward FDI, thereby recording negative aggregate industry-mix effects and negative aggregate competitive effects as well. However, the following industries have recorded positive competitive effect: electrical and electronic equipment, motor vehicles and other transport equipment, hotels and restaurants, transport, storage and communications, finance, and business services. In a nutshell, Korea is revealed to have competitive advantage in absorbing inward FDI in a few manufacturing industries and most of service industries. Government policies should accordingly be focused on these industries to encourage more inward FDIs.