• Management & Information Systems Review
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• v.32 no.5
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• pp.69-88
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• 2013

This study aimed to analyze the effects that the exchange relationship among employees engaged in the wedding industry in Busan, Ulsan and Gyeongnam area exerted on job satisfaction and voluntary service intentions. For this purpose, a theoretical model was presented based on previous studies and the relationship among variables was analyzed based on the analysis results through a survey. There have recently been great difficulties in the whole wedding industry due to the global economic depression and the low birthrate. Moreover, it is hard to optimize the future business environment. In particular, the low birthrate has weakened the demand base of the wedding industry. As a result, it is expected that the competition among companies will be more fierce in the wedding industry. Employees' voluntary service intention become much more important to overcome difficulties in this industry. Employees' voluntary service intentions can be possible when their job satisfaction is achieved. Many studies report the result that this job satisfaction can naturally be achieved when the high quality exchange relationship among a leader, team members (co-workers) and customers is formed. It is viewed that employees' voluntary service intentions should be induced through job satisfaction to improve the profitability through the efficient operation and management of the system. A leader of the organization should make an effort to form the high-quality exchange relationship with members, support so that team members(coworkers) and other employees can get along together and the teamwork can be improved and induce them to improve a high level of service quality with friendly customer services. In spite of the significance of the study discussed above, there are the following limitations in this study. There is a limit to a certain extent in generalizing study conclusions because the study was limited to the Busan, Ulsan and Gyeongnam area. If practical surveys which full- and part-time employees are included in the composition of samples are conducted for wedding suppliers in the country in the future, the quality of study will be able to improve.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.125-135
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• 2009

Statement of problem: Loosening or fracture of the abutment screw is one of the common problems related to the dental implant. Generally, in order to make the screw joint stable, the preload generated by tightening torque needs to be increased within the elastic limit of the screw. However, additional tensile forces can produce the plastic deformation of abutment screw when functional loads are superimposed on preload stresses, and they can elicit loosening or fracture of the abutment screw. Therefore, it is necessary to find the optimum tightening torque that maximizes a fatigue life and simultaneously offer a reasonable degree of protection against loosening. Purpose: The purpose of this study was to present the influence of tightening torque on the implant-abutment screw joint stability with the 3 dimensional finite element analysis. Material and methods: In this study, the finite element model of the implant system with external butt joint connection was designed and verified by comparison with additional theoretical and experimental results. Four different amount of tightening torques(10, 20, 30 and 40 Ncm) and the external loading(250 N, $30^{\circ}$) were applied to the model, and the equivalent stress distributions and the gap distances were calculated according to each tightening torque and the result was analyzed. Results: Within the limitation of this study, the following results were drawn; 1) There was the proportional relation between the tightening torque and the preload. 2) In case of applying only the tightening torque, the maximum stress was found at the screw neck. 3) The maximum stress was also shown at the screw neck under the external loading condition. However in case of applying 10 Ncm tightening torque, it was found at the undersurface of the screw head. 4) The joint opening was observed under the external loading in case of applying 10 Ncm and 20 Ncm of tightening torque. 5) When the tightening torque was applied at 40 Ncm, under the external loading the maximum stress exceeded the allowable stress value of the titanium alloy. Conclusion: Implant abutment screw must have a proper tightening torque that will be able to maintain joint stability of fixture and abutment.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.2
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• pp.75-85
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• 2015

Purpose: The purpose of this study is to evaluate which FRC-posts were more distinguishable from core. Materials and Methods: Nine extracted single-rooted mandibular premolars with similar lengths (${\pm}0.5 mm$) and widths (${\pm}0.5 mm$) were endodontically treated and obturated. One specimen which the three roots were embedded in a cold mounting resin was made. 3 specimens were made by this method. Post spaces were prepared for the following post system: FRC $Postec^{(R)}$ Plus, MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$, $Snowpost^{(R)}$. After three different posts were placed in the roots of a specimen, each three specimens received a direct core build-up: $Luxacore^{(R)}$ Dual A3, $Luxacore^{(R)}$ Dual blue, $Filtek^{TM}$ Z350 A1E. Digital images were taken of the post and core with and without air-blowing. We asked to fifty dentists and fifty dental college students which post was more clearly discriminated from the core. Results: In surveys, when core was $Luxacore^{(R)}$ Dual blue, among three types of posts people more easily discriminated the $Snowpost^{(R)}$ from core. When core was $Luxacore^{(R)}$ Dual A3, among three types of posts people similarly more easily discriminated $Snowpost^{(R)}$ from core. When core was $Filtek^{TM}$ Z350 A1E, among three types of posts people more easily discriminated distinguished MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ post from core. People more easily distinguished MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ post from core when temperature was lowered by air-blowing. Conclusion: Ability to discriminate between FRC-post and core is different according to color contrast. MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ posts are more discriminable when temperature is lowered by air-blowing.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.2
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• pp.106-110
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• 2020

The purpose of this study was to evaluate winter annual forage crops for yield, and horse palatability under horse grazing during the fall and spring in Jeju. The winter annual forage crops such as Italian ryegrass(IRG), rye, and oat were planted in randomized block design in October 30. The horse grazing was initiated on March 17 of the following year. At the first cutting, the dry matter yield of rye was the highest with 4,600 kg/ha compared to the IRG and oat (p<0.05). But there were no significantly different in the yield of winter annual forage crops after the second and third harvests. The total dry matter yield showed rye 12,593 kg/ha, IRG 10,941 kg/ha, and oat 9,424 kg/ha respectively. The horse intake duration of the IRG was significantly higher than the oat and rye (p<0.05). In the first grazing and the second grazing, the intake duration of the IRG was 853.2 seconds and 989.4 seconds, respectively, with oat at 147.6 seconds, and 73.0 seconds, and rye at 89.4 seconds, and 33.18 seconds. The intake duration of IRG was longer than that of oat and rye (p<0.05). The intake rate of the IRG was 60.0% in the first and 82.8% in the second, and the average intake rate was 71.4%. When considering the maintenance of pastures and the palatability of horses, the IRG is the most suitable forage crop in winter annual forage crops in Jeju.

• Journal of Society of Preventive Korean Medicine
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• v.6 no.2
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• pp.66-85
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• 2002

Traditional herbal medicine is used extensively among the Korean populations, and other Asian countries employ similar therapies as well In recent years, extensive focus was laid on adulteration of the herbal medicine with heavy metals. This may be mainly due to a soil contamination by an environmental pollution. The objective of this study is to identify the contents of various heavy metals in the blood from OhJeokSan-Decoction (OD) treated-rats. For this study, 13 kinds of metals including essential and heavy metals, i.e. Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn were analyzed by a slight modification of EPA methods and the following results are obtained. ; 1. There is no significant difference between the OD-treated groups and control group in liver, kidney, bone, brain, weight, food intake. 2. The amount of each metal analyzed in the liver are as follows; Al ; $0.235{\sim}4.215mg／kg$, As ; $0.103{\sim}0.461mg／kg$, Cd ; $0.005{\sim}0.010mg／kg$, Co ; $0.017{\sim}0.046mg／kg$, Cr ; $0.137{\sim}0.403mg／kg$, Cu ; $1.736{\sim}4.827mg／kg$, Fe ; $54.472{\sim}381.447mg／kg$, Hg ; not detected, Mn ; $1.159{\sim}2.803mg／kg$, Ni ; $0.007{\sim}0.095mg／kg$, Pb ; not detected, Se ; $0.682{\sim}1.887mg／kg$, Zn ; $10.213{\sim}26.119mg／kg$, by groups, respectively. In control and other experimental group, several metal (Co, Cu, Mn, Zn, As, Cr) has a significant difference, but in experimental I and other experimental II, III, IV, V groups, there are no significant difference. 3. The amount of each metal analyzed in the kidney are as follows; Al ; $1.712{\sim}31.230mg／kg$, As ; $0.062{\sim}0.439mg／kg$, Cd ; $0.010{\sim}0.062mg／kg$, Co ; $0.000{\sim}0.101mg／kg$, Cr ; $0.125{\sim}0.636mg／kg$, Cu ; $3.385{\sim}12.502mg／kg$, Fe ; $41.148{\sim}99.709mg／kg$, Hg ; $0.000{\sim}0.270mg／kg$, Mn ; $0.433{\sim}2.301mg／kg$, Ni ; $0.000{\sim}0.221mg／kg$, Pb ; $0.000{\sim}0.584mg／kg$, Se ; $0.540{\sim}1.600mg／kg$, Zn ; $8.775{\sim}17.060mg／kg$, by groups, respectively. The concentration of Cu, Se, Cr, and Hg are variated significantly in control and other experimental group, and Cu, Se, Cd, Cr are variated significantly in experimental I and other experimental II, III, IV, V groups. 4. The amount of each metal analyzed in the bone(tibia and fibula) are as follows; Al ; $9.557{\sim}119.464mg／kg$, As ; $0.139{\sim}12.250mg／kg$, Cd ; $0.000{\sim}0.295mg／kg$, Co ; $0.022{\sim}0.243mg／kg$, Cr ; $0.239{\sim}1.999mg／kg$, Cu ; $0.000{\sim}2.291mg／kg$, Fe ; $240.249{\sim}841.956mg／kg$, Hg ; $0.000{\sim}0.983mg／kg$, Mn ; $0.214{\sim}7.353mg／kg$, Ni ; $5.473{\sim}11.453mg／kg$, Pb ; $0.000{\sim}8.502mg／kg$, Se ; $0.000{\sim}3.005mg／kg$, Zn ; $61.158{\sim}195.038mg／kg$, by groups, respectively. The concentration of Se, Cd are variated significantly in control and other experimental groups, and Se is variated significantly in experimental I and other experimental II, III, IV, V groups. 5. Exceptionally several metal concentration is increased or decreased. but there is no significant harmful difference of metal concentration in the liver, kidney and bone, from the OD-treated-rats compared to those of the control group even if higher dosage($1{\sim}8$ times dosage of person) of OD was administered. Thus, it is expected that the herbal decoction in the traditional herbal medicine would not lay any burden on the body and the heavy metal toxins would not affect our physiological system. However, other kinds of herbal treatment, such as i.v. and i.p. should be considered in terms of metal toxicity in the body since the level of certain metal.

• Journal of the Korean Institute of Navigation
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• v.4 no.2
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• pp.45-79
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• 1980

The aim of this paper is to analyze the mechanics of price formation in the tramp shipping. For the purpose of this study, the main characteristics of tramp freight rates and the market is examined, and a brief examination of the nature ofthe costs of operation is given which are essential for the understanding of the functioning of shipping firms as well as for the understanding of developments in the tramp freight market. The demand and supply relationships in the market is also analysed in detail. Tramp shipping is an industry that has a market which functions under conditions that are not dissimilar to the theoretical model of perfect competition. However, it does notmean that tramp shipping market is a perfectly competitive market. It is apparent that this realworld competitive system has its imperfections, which means that the market for tramp shipping is near to being a perfectly competitive market on an internaitonal scale and it is freight are therefore subjext to the laws of supply and demand. In theory, the minimum freight rate in the short term is that at which the lowest cost vessels will lay-up in preference to operating, and is equal to the variable costs minus lay-up costs; and this would imply that in all times except those of full employment for ships there is a tendency for newer low-cost, and, probably, faster vessels to be driving the older high-cost vessels in the breaker's yards. In this case, shipowners may be reluctant to lay-up their ships becasue of obligations to crews, or because they would lose credibility with shippers or financiers, or simply because of lost prestige. Mainly, however, the decision is made on strictly economic grounds. When, for example, the total operating costs minus the likely freight earnings are greater than the cost of taking the ship out of service, maintaining it, and recommissioning it, then a ship may be considered for laying-up; shipowners will, in other words, run the ships at freight earnings below operating costs by as much as the cost of laying them up. As described above, the freight rates fixed on the tramp shipping market are subject to the laws of supply and demand. In other words, the basic properties of supply and demand are of significance so far as price or rate fluctuations in the tramp freight market are concerned. In connection with the same of the demand for tramp shipping services, the following points should be brone in mind: (a) That the magnitude of demand for sea transport of dry cargoes in general and for tramp shipping services in particular is increasing in the long run. (b) That owning to external factors, the demand for tramp shipping services is capable of varying sharphy at a given going of time. (c) The demad for the industry's services tends to be price inelastic in the short run. On the other hand the demand for the services offered by the individual shipping firm tends as a rule to be infinitely price elastic. In the meantime, the properties of the supply of the tramp shipping facilities are that it cannot expand or contract in the short run. Also, that in the long run there is a time-lag between entrepreneurs' decision to expand their fleets and the actual time of delivery of the new vessels. Thus, supply is inelastic and not capable of responding to demand and price changes at a given period of time. In conclusion, it can be safely stated that short-run changes in freight rates are a direct result of variations in the magnitude of demand for tramp shipping facilities, whilest the average level of freight rates is brought down to relatively low levels over prolonged periods of time.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.29-38
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• 2010

A moat is a pond or waterway paved on the outside of a fortress that is one of the facilities to prevent enemy from approaching the fortress wall or classify it as the boundary space, and this study was undertaken to find out the characteristics of the moat that was existed in the East and the West from ancient time to medieval time with the following result. First, the moat in the East was installed of natural moat and artificial moat at the same time while the moat in the West had the fortress built in naturally advantageous site to use natural most substantially more. Second, the moats of Korea were smaller in scale compared to other countries (Japan, China and the Western countries). Third, the fortresses in the East were built to protect towns or royal palace while the West had the fortress to protect the residence of kings, lords, great wealthy persons and the like, and they were used jointly with the natural moat and artificial moat to defend against the infiltration of enemy. Fourth, the Pungsujiri in the Orient is one of the numerous ideologies forming the supplementary ideologic system of Korean people that could not be denied as the perception that influences on Korean people after the Silla Dynasty, and this Pungsujiri was considered when determining the location of the castle. The moat surrounding the castle had the role to keep the good energy in the castle from escaping away. Fifth, the Ha-Ha technique in the west was designed to prevent the external power from infiltration by digging the ditch on the place applicable to the boundary of the garden site, rather than the fence. While walking around along the water-side path without knowing the existence of this ditch, when the road is discovered with the cut off in the ditch, people had the exclamation without actually recognizing such astonishment. It was originally the dike for military purpose during the medieval time that was designed to look into the garden without physical boundary surrounded with the vertical fence in the garden that by having the deep ditch like shape on the boundary line of the garden which was designed to form the farm by preventing various types of cattle from coming inside the garden and bring in the garden element for farms, forestry, agricultural land and the like.

• Archives of design research
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• v.19 no.2 s.64
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• pp.31-42
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• 2006

This study originates from the following critical mind; what will the office of the future be like? and what technology will we rely upon most to communicate with colleagues or to access business information. In the office environment today, new technology has compelled new work paradigm and has greatly affected the capabilities of the individual to work in a more productive and efficient manner. However, even though new computer technology has changed the business world so rapidly, it is very difficult to see the changes that have been taken place. As an aim of the study, creating a mobile tool for office workers that successfully supports their work and communication was explored, and this study explored future work environment with a 5 years technological and social perspective. As a result of this study, the bON brings new visions to the mobile professionals via various interfaces. The bON, a mobile device, is both a system of work and of communication for office workers. The bON, as an integrated tool for working and communicating, forms the basis for a mobile information gateway that is equally capable of functioning as a mobile desk. The basic underlying idea is that all formal meeting places and hallways in the office are equipped with large wall-mounted screens. The bON collaborates with these media in various ways to enhance productivity and efficiency. The main challenge for the bON to enhance both mobility and quality of information is using new technology including bendable and flexible display and soft material display and sensors. To answer for the strong needs for mobility, the whole size of the device is fairly small while the screen is rolled inside the device. For Graphical User Interface, moreover, a new technique called Multi-layering Interface was adopted to stretch user's visual limits and suggests new direction in designing mobile device, equipped with small size display.

• Journal of Intelligence and Information Systems
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• v.21 no.3
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• pp.117-129
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• 2015

As the Internet becomes ubiquitous, a large volume of information is posted on the Internet with exponential growth every day. Accordingly, it is not unusual that investors in stock markets gather and compile firm-specific or market-wide information through online searches. Importantly, it becomes easier for investors to acquire value-relevant information for their investment decision with the help of powerful search tools on the Internet. Our study examines whether or not the Internet helps investors assess a firm's value better by using firm-level data over long periods spanning from January 2004 to December 2013. To this end, we construct weekly-based search volume for information technology (IT) services firms on the Internet. We limit our focus to IT firms since they are often equipped with intangible assets and relatively less recognized to the public which makes them hard-to measure. To obtain the information on those firms, investors are more likely to consult the Internet and use the information to appreciate the firms more accurately and eventually improve their investment decisions. Prior studies have shown that changes in search volumes can reflect the various aspects of the complex human behaviors and forecast near-term values of economic indicators, including automobile sales, unemployment claims, and etc. Moreover, search volume of firm names or stock ticker symbols has been used as a direct proxy of individual investors' attention in financial markets since, different from indirect measures such as turnover and extreme returns, they can reveal and quantify the interest of investors in an objective way. Following this line of research, this study aims to gauge whether the information retrieved from the Internet is value relevant in assessing a firm. We also use search volume for analysis but, distinguished from prior studies, explore its impact on return comovements with market returns. Given that a firm's returns tend to comove with market returns excessively when investors are less informed about the firm, we empirically test the value of information by examining the association between Internet searches and the extent to which a firm's returns comove. Our results show that Internet searches are negatively associated with return comovements as expected. When sample is split by the size of firms, the impact of Internet searches on return comovements is shown to be greater for large firms than small ones. Interestingly, we find a greater impact of Internet searches on return comovements for years from 2009 to 2013 than earlier years possibly due to more aggressive and informative exploit of Internet searches in obtaining financial information. We also complement our analyses by examining the association between return volatility and Internet search volumes. If Internet searches capture investors' attention associated with a change in firm-specific fundamentals such as new product releases, stock splits and so on, a firm's return volatility is likely to increase while search results can provide value-relevant information to investors. Our results suggest that in general, an increase in the volume of Internet searches is not positively associated with return volatility. However, we find a positive association between Internet searches and return volatility when the sample is limited to larger firms. A stronger result from larger firms implies that investors still pay less attention to the information obtained from Internet searches for small firms while the information is value relevant in assessing stock values. However, we do find any systematic differences in the magnitude of Internet searches impact on return volatility by time periods. Taken together, our results shed new light on the value of information searched from the Internet in assessing stock values. Given the informational role of the Internet in stock markets, we believe the results would guide investors to exploit Internet search tools to be better informed, as a result improving their investment decisions.

• Journal of Intelligence and Information Systems
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• v.21 no.3
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• pp.19-36
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• 2015

Social media is an emerging issue in content services and in current business environment. YouTube is the most representative social media service in the world. YouTube is different from other conventional content services in its open user participation and contents creation methods. To promote a content in YouTube, it is important to understand the diffusion phenomena of contents and the network structural characteristics. Most previous studies analyzed impact factors of contents diffusion from the view point of general behavioral factors. Currently some researchers use network structure factors. However, these two approaches have been used separately. However this study tries to analyze the general impact factors on the view count and content based network structures all together. In addition, when building a content based network, this study forms the network structure by analyzing user comments on 22,370 contents of YouTube not based on the individual user based network. From this study, we re-proved statistically the causal relations between view count and not only general factors but also network factors. Moreover by analyzing this integrated research model, we found that these factors affect the view count of YouTube according to the following order; Uploader Followers, Video Age, Betweenness Centrality, Comments, Closeness Centrality, Clustering Coefficient and Rating. However Degree Centrality and Eigenvector Centrality affect the view count negatively. From this research some strategic points for the utilizing of contents diffusion are as followings. First, it is needed to manage general factors such as the number of uploader followers or subscribers, the video age, the number of comments, average rating points, and etc. The impact of average rating points is not so much important as we thought before. However, it is needed to increase the number of uploader followers strategically and sustain the contents in the service as long as possible. Second, we need to pay attention to the impacts of betweenness centrality and closeness centrality among other network factors. Users seems to search the related subject or similar contents after watching a content. It is needed to shorten the distance between other popular contents in the service. Namely, this study showed that it is beneficial for increasing view counts by decreasing the number of search attempts and increasing similarity with many other contents. This is consistent with the result of the clustering coefficient impact analysis. Third, it is important to notice the negative impact of degree centrality and eigenvector centrality on the view count. If the number of connections with other contents is too much increased it means there are many similar contents and eventually it might distribute the view counts. Moreover, too high eigenvector centrality means that there are connections with popular contents around the content, and it might lose the view count because of the impact of the popular contents. It would be better to avoid connections with too powerful popular contents. From this study we analyzed the phenomenon and verified diffusion factors of Youtube contents by using an integrated model consisting of general factors and network structure factors. From the viewpoints of social contribution, this study might provide useful information to music or movie industry or other contents vendors for their effective contents services. This research provides basic schemes that can be applied strategically in online contents marketing. One of the limitations of this study is that this study formed a contents based network for the network structure analysis. It might be an indirect method to see the content network structure. We can use more various methods to establish direct content network. Further researches include more detailed researches like an analysis according to the types of contents or domains or characteristics of the contents or users, and etc.