• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.141-157
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• 2007

This paper evaluates the effects of privatization and deregulation on the firm-specific efficiency and total factor productivity (TFP) growth in the Korean and Japanese railways. Using a stochastic frontier approach and a generalized translog functional form, the paper specifies the equation system consisting of a multiproduct variable cost function and input share equations which is estimated with Zellner's iterative seemingly unrelated regression and the corrected least squares method. The Korean and Japanese railway firms are assumed to produce three outputs (Shinkansen passenger-kilometers, incumbent railway passenger-kilometers, ton-kilometers of freight) using three input factors (labor, fuel, maintenance and rolling stock). A monetary value of the ways and fixed installations held by the railroad firm is also included as a quasi-fixed input. The empirical results indicate that the average estimate of cost inefficiency is 2.57% for the total sample and on the average, JNR and JR Kyushu are found to be worst efficient while the most efficient railway firm in the sample is JR West. Also the cost efficiency levels of seven JRs have been improved after the reform and privatization of JNR. The findings also indicate that TFP growth of the privately-owned JRs are higher than those of the government-owned KNR and JNR. Three-island JRs and JR Freight have slightly higher TFP growth than Honshu JRs as well. Thus, the results suggest that managerial autonomy and increased competition via deregulation have improved efficiency and TFP growth.

• Elastomers and Composites
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• v.48 no.3
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• pp.201-208
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• 2013

In this study, effect of different amounts of sulfur and vulcanization accelerators in the acrylonitrile styrene-butadiene rubber (AN-SBR)/silica compounds on the properties of tire tread compound were studied. As a result, cure rate and degree of cross-linking of the compounds were increased due to enhanced cross-linking reactivity by the increased amounts of sulfur and vulcanization accelerators. Also, abrasion resistance and the mechanical properties such as hardness and modulus of the compounds were improved by enhanced degree of cross-linking of the compounds. For the dynamic properties, tan ${\delta}$ value at $0^{\circ}C$ was increased due to the increase of glass transition temperature ($T_g$) by enhanced degree of cross-linking of the compound, and tan ${\delta}$ value at $60^{\circ}C$ was decreased. Initial cure time ($t_1$) showed the linear relationship with tan ${\delta}$ value at $60^{\circ}C$. This result is attributed that reduced initial cure time ($t_1$) of compounds by applying increased amount of curatives can form cross-linking in early stage of vulcanization that may suppress development of filler network. This result is verified by observation on the surface of annealed compounds using AFM (atomic force microscopy). Consequently, decreased initial cure time is considered a very important parameter to reduce tan ${\delta}$ at $60^{\circ}C$ through reduced re-agglomeration of silica particles.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.189-201
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• 1977

Some of basic aspects of soil potassium with special reference to soil physical properties were discussed. Data in the Official Soil Series Description(Korea) was analyzed according to soil type, land form, and soil texture to find soil potassium status which may explain different response to potassium application. Exchangeable potassium contents decreased with soil depth irrespective of soil type, land form and soil texture. Change in degree of potassium saturation within soil profile was not so clear as exchangeable potassium but the degree of potassium saturation of A horizon was highest among soil horizon. Soils of terrace and mountain foot slope showed high values both in exchangeable potassium and degree of potassium sauration and only these two soils were classified as soils having exchangeable potassium higher than 0.3 meq per 100g of soil and degree of potassium saturation higher than 5.0%. Exchangeable potassium of fine loamy and fine clayey soils is higher than 0.3 meq per 100g of soil but degree of potassium saturation is lower than 4.0%. Degree of potassium saturation of sandy soils exceeds 5.0% but exchangeable potassium is very low. Soils of rolling, hilly, unmatured and alpine land soils have lower exchangeable potassium and show lower degree of potassium saturation. The highest distribution of exchangeable potassium content irrespective of soil horizons was shown in the range of 0.1-0.2 meq per 100g of soil. The highest distribution of degree of potassium saturation was in the range of 2.0-3.0% in A horizon and 1.0-2.0% in B and C horizons. Of the soil series concerned in this analysis, 27.3% in A horizon, 11.1% in B horizon and 4.0% in C horizon had exchangeable potassium higher than 0.3 meq per 100g of soil and 18.0% in A horizon, 6.3% in B horizon, and 4.1% in C horizon showed degree of potassium saturation higher than 5.0%. The low response of potassium application only to soils in terrace and mountain foot slope may be resulted from the high exchangeable potassium content and high degree of potassium saturation. It is concluded that a great response of potassium application to soils is expected especially in dry season.

• Journal of Fashion Business
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• v.1 no.1
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• pp.71-83
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• 1997

The purpose of this study is to analyze the present fashion phenomenon by considering the types of street fashion, the center of avant-grade modern fashion, that shows the origination background and special feature concretely. The times was defined through the 1980's from World War II that street style originated, so the range of study was the 1990's when the street style was influenced by that of the past and was revived. The ways of study were to analyze the records of ideology, art and music connected with the street style from World War II to the present when it has risen. The summary of result is as follows. (1) In the 1940's, Zooties was the jet of desire suppressed by African-Americans that couldn't receive favors socially and economically and Hipsters pursued reformative bebop that made up of soft Jazz. In the 1950's, Modernists were running after Cool Jazz to the minimum. In the 1970's, Funk appered in the sexual desire and erotic strength, and was surfaced from Negro Getto. In the 1980's B-boys & Flygirls showed the street style by the scribble art of slum in the New York. As mentioned above, In the 1990's, Acid Jazz influenced by the Jazz of Negro has been the fashion added to the tradition of musical form that come from eclecticism of Jazz tended Neo-Jazz. (2) In the 1940's, Western style dreamed the country life because of rapid urbanization. In the 1950's, Beat obtained the feeling of liberation from the dissolute life and activity. In the 1960's, Psychedelics showed the freedom affected by the Pop-art and Op-art, and Hippies pursued the true individuality as 'love & peace' life style and the return to nature. In the 1990's, Grunge look influenced by the above has been fashion that shows the practical use of second-hand clothing or patchwork contrary to elitism. (3) In the 1940's, Caribbean style appered in the typical textile color with the center of West Indies. In the 1960's, Rude boys showed the magnificence and difficulty of Jamaica, and Rastafarians had a tendency to come back to the ancient civilization of America. In the 1970's, Two-tone was the simple clothing for harmonizing among human races. In the 1990's, Jamaica look influenced by the above has been the Lege fashion introduced to a high fashion, appearing in the special bright color, applique, unique hair style, and so on. (4) In the 1950's, Sufers pursued natural rhythm, getting out of everything. In the 1970' s, Skaters enjoyed the speed on the paved road. In the 1980's, Casuals emphasized the spirit of cooperation of young-things. In the 1990's, Casual look Influenced by the above has been the fashion that forms the activity, function and strong spirit of cooperation by pursuing comfortable life and sports in the tension of life and variety of modern society. (5) It was hard for Bikers to adjust themselves in society after the war. In the 1950's, Coffee bar cowboys were the reckless running boys in the leather jacket. In the 1960's, Rockers created the group originality as disobedient outsiders and Greasers imitated Rolling Stones. In the 1980's, Punks resisted the viewpoint of the old generation in offensive fashion. In the 1990's, Cyberpunk influenced by the above has pursued the classless structure, electronic music and metallic clothing that forebodes gloomily as the computer generation of ultra-modern science times. Accordingly, in understanding a complex modern fashion phenomenon, it was analyzed that the street styles of the past, from World War II to the 1980's, were reflected in that of the 1990's dividing into the five types in a word, namely Acid Jazz, Grunge look, Jamaica look, Casual look and Cyberpunk.

• Asia pacific journal of information systems
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• v.20 no.1
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• pp.127-140
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• 2010

The benefit that a consumer derives from the use of a good often depends on the number of other consumers purchasing the same goods or other compatible items. This property, which is known as network externality, is significant in many IT related industries. Over the past few decades, network externalities have been recognized in the context of physical networks such as the telephone and railroad industries. Today, as many products are provided as a form of system that consists of compatible components, the appreciation of network externality is becoming increasingly important. Network externalities have been extensively studied among economists who have been seeking to explain new phenomena resulting from rapid advancements in ICT (Information and Communication Technology). As a result of these efforts, a new body of theories for 'New Economy' has been proposed. The theoretical bottom-line argument of such theories is that technologies subject to network effects exhibit multiple equilibriums and will finally lock into a monopoly with one standard cornering the entire market. They emphasize that such "tippiness" is a typical characteristic in such networked markets, describing that multiple incompatible technologies rarely coexist and that the switch to a single, leading standard occurs suddenly. Moreover, it is argued that this standardization process is path dependent, and the ultimate outcome is unpredictable. With incomplete information about other actors' preferences, there can be excess inertia, as consumers only moderately favor the change, and hence are themselves insufficiently motivated to start the bandwagon rolling, but would get on it once it did start to roll. This startup problem can prevent the adoption of any standard at all, even if it is preferred by everyone. Conversely, excess momentum is another possible outcome, for example, if a sponsoring firm uses low prices during early periods of diffusion. The aim of this paper is to analyze the dynamics of the adoption process in markets exhibiting network effects by focusing on two factors; switching and agent heterogeneity. Switching is an important factor that should be considered in analyzing the adoption process. An agent's switching invokes switching by other adopters, which brings about a positive feedback process that can significantly complicate the adoption process. Agent heterogeneity also plays a important role in shaping the early development of the adoption process, which has a significant impact on the later development of the process. The effects of these two factors are analyzed by developing an agent-based simulation model. ABM is a computer-based simulation methodology that can offer many advantages over traditional analytical approaches. The model is designed such that agents have diverse preferences regarding technology and are allowed to switch their previous choice. The simulation results showed that the adoption processes in a market exhibiting networks effects are significantly affected by the distribution of agents and the occurrence of switching. In particular, it is found that both weak heterogeneity and strong network effects cause agents to start to switch early and this plays a role of expediting the emergence of 'lock-in.' When network effects are strong, agents are easily affected by changes in early market shares. This causes agents to switch earlier and in turn speeds up the market's tipping. The same effect is found in the case of highly homogeneous agents. When agents are highly homogeneous, the market starts to tip toward one technology rapidly, and its choice is not always consistent with the populations' initial inclination. Increased volatility and faster lock-in increase the possibility that the market will reach an unexpected outcome. The primary contribution of this study is the elucidation of the role of parameters characterizing the market in the development of the lock-in process, and identification of conditions where such unexpected outcomes happen.