• Journal of The Korean Astronomical Society
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• v.50 no.6
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• pp.167-178
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• 2017

We present a study of the inexplicit connection between radio jet activity and ${\gamma}$-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two ${\gamma}$-ray outbursts (in November 2013 and March 2015) can be seen in ${\gamma}$-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of $411{\pm}85$ days, $352{\pm}79$ days, $310{\pm}57$ days, and $283{\pm}55$ days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths $B{\sim}2{\mu}T$ and electron Lorentz factors ${\gamma}$ ~ 10 000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we find that the decay timescale ${\tau}$ scales with frequency ${\nu}$ like ${\tau}{\propto}{\nu}^{-0.2}$. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the ${\gamma}$-ray outbursts. The spectral evolution is consistent with the 'generalized shock model' of Valtaoja et al. (1992). A temporary increase in the core opacity and the emergence of a knot around the time of the second ${\gamma}$-ray event indicate that this ${\gamma}$-ray outburst might be an 'orphan' flare powered by the 'ring of fire' mechanism.

• Korean journal of communication and information
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• v.16
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• pp.36-70
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• 2001

The purpose of this study is to investigate women's radio talk program and evaluate its possibilities and limitation from the point of feminist perspective. The theoretical framework is based on feminist studies and text analysis of talk show. Existing studies regarding talk show are mainly focused on television. But radio talk show is one of general entertainment and it's influences on minorities are still significant. is the most representative women's radio talk program in Korea. It has been broadcasted over 10 years and very popular among Korean housewives. The audience of this program call themselves schoolfellow, and call the program 'school of women'. The media text of is mainly consisted of letters from women audiences, and they are selected by producers. So the text is made by both audiences and producers. The unique combination of this process produces complicated discourses which contain women's experiences in letters and station's considerations through safekeeping. The problems investigated in this study are as follows: First, What discourses are produced in this program? Second, Alternative possibilities can be seen in this program in feminist perspectives? Text analysis of 1week(2000.9.18-9.24) and interview with producers are accomplished to this purposes. In the text analysis, subject matters, inscribed women's position, values of the letters are revealed. Most of the subject matters are family affairs. Some are socially oriented but family and home are the predominant category of women's letters. And the position of women subject is defined in the domestic network. They are nameless but the mother, wife, daughter, daughter-in-law of other people. In value, family-oriented value and small happiness in everyday life are generally appeared. But these values are essentially coincide with the values of status quo. The answers of the conflict are not public but individualized. And acception the status quo is presented as the wisest decision, But ` has many implications in relation to women's sharing of their experience, and construction of imagined community in media. Women continuously interact each other revealing and discussing their experiences and sometimes their social practices are stirred through this media sphere. So we see the 'emotional union' among women are formed through radio. The limitation of this program is very apparent: it's patriarchic values, acception of status quo, and individualization of the women's problems. But in the same time we can read coexisting it's latent possibilities: the possibilities of women's public sphere. But it is completely alternative women's sphere in feminist perspectives. It renders women opportunities to participate public media and share with other women, and collaborate with their problem.

• Journal of Environmental Impact Assessment
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• v.25 no.1
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• pp.1-14
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• 2016

With the continuous expansion of highway network and its traffics, neighboring wildlife habitats are splitted into smaller and more isolated patches. The infrastructures contribute to the wildlife-vehicle collision by creating barriers to animal movement. This kinds of traffic accidents are dangerous factors to the drivers' safety and the facilities on the highway as well as to the wildlife themselves. One of the most common ways to prevent habitat fragmentation are fauna crossings and fences. The cost of the mitigation measures to prevent wildlife-vehicle collision could be monetized. However their economic benefits are difficult to be measured. Using contingent valuation method, this study tries to estimate the economic valuation of wildlife collision prevention projects on the Korean highways. The result shows that 43.88% of Korean household had the positive willingness pay to the projects. Moreover, we found that the recognition of the project or the favourable attitude to the environmental issues could raise the willingness-to-pay. Therefore, active public relation on the project could make the friendly public opinion and increase the number of the household which has the positive willingness-to-pay on the project.

• Korean Journal of Materials Research
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• v.7 no.1
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• pp.81-88
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• 1997

Vanadate glasses using $B_2O_3$ as a network former and with CuO additive were mainly investigated in relation to electrical properties. Crystalline phases formed by heat-treatment in each composition were examined and dc electrical conductivity changes of the glasses were analyzed. Crystalline phases were identified as $V_3O_5,\;a-CuV_2O_6\;and\;{\beta}-CuV_2O_6$ by XRD analysis. Crystallization degrees of $V_2O_5$ and ${\beta}-CuV_2O_6$ were little changed with heat-treatment time, but those of ${\alpha}u-CuV_2O_6$ were changed sharply with heat-treatment time. The more crystallization of ${\alpha}u-CuV_2O_6$ occurred, the higher electrical conductivity was observed. Electrical conductivities with $10^{-2}~10^{-4}/{\Omega}/cm$ at room temperature(303K) could be obtained by controlling the glass compositions. The electrical conductivities were increased with increasing of $V_20_5$ content and decreasing of alkality($CuO/B_2O_3$). In this study, electron was proved to be charge carrier by seebeck coefficient measurement. Accordingly, the glasses are believed to be n-type semiconductor. Calculated activation energies for the conduction were in the range 0.098-0.124 eV. Electrical conduction mechanism was small polaron hopping without showing variable range hopping in the temperature range $30~200^{\circ}C$.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.263-276
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• 2008

In diverse hydrogeologic fields, estimation of groundwater storage change is one of the most critical issues. Accurate estimation methods for determining groundwater storage change are required more and more. For Yeonyang area of Ulsan Megacity, groundwater storage change was estimated by using water balance method and hydrogeological analyses. The estimates of groundwater storage change was 240 mm corresponding to 18.7% of mean annual precipitation. Direct runoff was calculated as 137 mm (10.6% of mean annual precipitation) by using SCS-CN method. Evapotranspiration based on the Thornthwaite method was calculated as 776 mm (60.5% of mean annual precipitation). Hydraulic properties of the soil types do not show any distinct relation with hydraulic conductivity of the rocks. This fact suggests that hydraulic property on the surface is different from that of subsurface geology. According to multi-linear regression analysis between groundwater storage change and hydraulic parameters, a regression equation of groundwater storage change, which was explained by precipitation and evapotranspiration, was established.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.6
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• pp.623-634
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• 2003

In this paper, we propose a collaborative multimedia authoring system. Our authoring system represents a multimedia presentation in a 3D coordinate system. One axis represents the traditional timeline information (T-zone), and the other two axes represent spatial coordinates (XY-zone). Our system represents a visual media objects as a 3D parallelepipeds and audio media objects as cylinders. This interface allows for simultaneous authoring and manipulation of both the temporal and the spatial aspects of a presentation. Using our system, users can design multimedia presentations collaboratively in the unified spatio-temporal space while freely traversing the spatial domain and the temporal domain without changing the context of authoring. In addition, we suggest an efficient mechanism of concurrency control for shared objects generated by our collaborative writing system. The mechanism is mainly based on the user awareness, the multiple versions, and the access permission of shared objects. Our concurrency control mechanism is designed to keep data consistency by minimizing the collision due to the delay or the failure of network communication and to allow maximum responsiveness for users using optimistic concurrency control. Also, the mechanism maximize the responsiveness by refining the locking granularity and applying different concurrency control mechanisms to each.

• Journal of KIISE:Databases
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• v.34 no.5
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• pp.448-464
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• 2007

Location-Based Services (LBSs) provide results to queries according to the location of the client issuing the query. In LBS, techniques such as caching and prefetching are effective approaches to reducing the data transmission from a server and query response time. However, they can lead to cache inefficiency and network overload due to the client's mobility and query pattern. To solve these drawbacks, we propose a semantic prefetching (SP) scheme using prefetching segment concept and improved cache replacement policies. When a mobile client enters a new service area, called semantic prefetching area, proposed scheme fetches the necessary semantic information from the server in advance. The mobile client maintains the information in its own cache for query processing of location-dependent data (LDD) in mobile computing environment. The performance of the proposed scheme is investigated in relation to various environmental variables, such as the mobility and query pattern of user, the distributions of LDDs and applied cache replacement strategies. Simulation results show that the proposed scheme is more efficient than the well-known existing scheme for range query and nearest neighbor query. In addition, applying the two queries dynamically to query processing improves the performance of the proposed scheme.

• The Journal of Engineering Geology
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• v.11 no.3
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• pp.327-337
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• 2001

To verify the characteristics of groundwater inflow accompanied by the tunnel excavation, the flow rate was measured before and after primary grouting. The relationship between the flow rate and fracture system was also analyzed. The initial flow rate was estimated as 120,990 m$^3$/day through six zones, which were characterized by a large amount of inflow before the primary grouting. After the primary grouting, although considerable amount of inflow was still recognized at the six zones, the flow rate was greatly reduced as 42,844 m$^3$/day. However, great recovery of water levels was not observed. Groundwater flow into the tunnel by excavation of the tunnel is mainly controlled by the fracture system that include faults and joints developed in the host rocks. Four sets of discontinuities affecting on the network of grondwater inflow in the study area were identified as follows: N60-85$^{\circ}C$ W.25$^{\circ}$SW/80$^{\circ}$SW(TSet 1), N40-50$^{\circ}$E.85$^{\circ}$SE/85$^{\circ}$NE(TSet 2), N10-20$^{\circ}$E.85$^{\circ}$SE(TSet 3), and N70-80$^{\circ}$E.80SE(TSet 4).

• Korean Journal of Social Welfare
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• v.58 no.2
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• pp.167-195
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• 2006

The purpose of this study is to suggest the revision direction of the Korean Child Welfare Law based on the results of the comparative analysis on the Korean Child Welfare Law and the Japanese Child Welfare Law. The main results are: Both laws have only two provisions about children's participation right. The child protective system in Japan secures the swiftness of within-two-months period of temporary protection through the child consulting center, the investigation right by the child welfare worker, publicity, enforcement on the parents' rights, and the network with the nearest child supporting center. Furthermore, those provisions with the notifying obligation by a finder of the child who needs protection and the limit of protection period are guaranteed in order to ensure the effectiveness of law enforcement. However, Korean child protective system functions only as pre-substitutive service. While the provisions for the disability children account for 21.2% of the total Japanese law, there is no provision on that in the Korean law. The Japanese law is substantially different from the Korean law in a sense that it obligates the minimum quality criteria of child service and national financial burden on the child welfare. While the Japanese law clearly stipulates the national responsibility in relation to the degree of the rights, the Korean law does not directly touch upon it. Furthermore, the Japan's law guarantees that not only children but also protectors retain the right to choose and apply for services.

• Journal of Distribution Science
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• v.13 no.12
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• pp.95-103
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• 2015

Purpose - The Visegrád Group cooperation of the past 14 years and that of V4 for the past 20 years has very important significance in the 21st century that must be maintained. This cooperation is valuable because of the trade routes that connect northern Poland to the Balkans in southern Croatia, which forman important basis for the resuscitation of Central European development. Currently, because of the European manufacturing base and industrial development, an energy supply and stable energy distribution networks have been introduced to secure cooperation and not competition within the Visegrád Group. This paper's research emphasizes the supply chain hub in neighboring countries. Although Central and Eastern European countries are small, they can provide a competitive response to Western Europe if they collaborate with the V4 group and other countries. Research design, data, and methodology - The subjects of this study in the Visegrád Group area are related to the development of Marketing and Distribution Sciences in the integrated European Union. In relation to the existing energy infrastructure, construction companies and financial institutions benefit from large-scale construction projects. Existing or new infrastructure facilities among the V4 must comply with the preconditions of regional energy markets. The network of emerging markets is changing into a European-logistics hub of new markets. This hub is closely associated with the economic development of European self-sustainment given that energy for distribution and consumption is imported from Russia. Therefore, this paper indirectly provides data on the regional distribution of energy as alternative bases in Europe for market expansion to Asia. Results - As a result, it appeared unlikely that V4 failed to implement homogeneity following the standards of Western Europe, as proposed by the EU. Throughout European history, individuals have gathered in Central Europe as an innovation hub. Currently, the region is being established independently for energy industrial development and not for tourism development, and is expected to play a central role in innovation and distribution consumption. Therefore, similar to Western and Northern Europe, V4 only appears to engage in distribution consumption on the basis of the identity that it formed for itself. This area is expected to either create a regional platform or a voice over a single economic policy. Conclusions - To this end, regarding the distribution of consumer groups within and outside the region, the V4 group is expected to be established for various policy areas and as a Eurasian outpost of trade and distribution logistics. In addition, given its purpose of engaging in the distribution of energy cooperation and trade clusters, the Visegrád Group will be in charge of the center axis of the bridge for distribution logistics trading partners from the Western Balkans to Caucasus and Eastern Europe. Thus, the Visegrád Group is entering this region as a platform for market share by enabling all or any investor can gain greater industrial benefits.