• Korean Journal of Agricultural Science
• /
• v.6 no.1
• /
• pp.45-55
• /
• 1979

This study made to find the variation of strengths of briquette ash which were hardened into cement. The briquette ash were mixed with the cement, ((cement (90%)+slaked lime (10%)) and ((cement (80%)+fly ash (20%)) in the ratio of 1:2, 1:3, 1:4, 1:5, 1:7 and 1:9, respectively, and these were compared with the one made of cement plus standard sand in the strengths of compression, tension and bending at the ages of 7 days and 28 days. The results from the study conducted preliminary without studying the economical aspects or duration of the products are summarized as follows: 1. The compressive strengths of mortar made of 1 to 2 ratios of cement to briquette ash, (cement+slaked lime) to briquette ash and (cement+fly ash) to briquette ash were 84%, 90% and 75% at the age of 7 days and 84.9%, 73.5% and 69.8%, respectively of those of Korean Standard values. 2. The compressive strength s of mortar made of 1 to 2 ratios of cement to briquette ash, (cement+slaked lime) to briquette ash and (cement+fly ash) to briquette ash were 69.3%, 75.1% and 41.3% at the age of 7 days and 56.4%, 49%, and 46.5% at the age of 28 days, respectively of the mortar made of standard sand. 3. The tension strengths of mortar made of 1 to 2 ratios of cement to briquette ash, (cement+slaked lime) to briquette ash, and (cement+fly ash) to briquette ash were 64.4%, 47.1% and 35.4% at the age of 7days and 69.6%, 64.8%, and 57.3%, respectively of that of the mort ar produced with standard sand. 4. The bending strengths of mortar made of 1 to 2 ratios of cement to briquette ash, (cement+slaked lime) to briquette ash, and (cement+fly ash) to briquette ash were 46.3%, 65.9% and 39.1% at the age of 7 days and 89.9%, 96.7%, and 85.1%, respectively of that of mortar produced with standard sand. 5. The bending strength of the mortar was lower than that of cement mortar, when the briquette ash were harqened into cement. However, the mortar produced by such method seemed to be used as the secondary products of cement or concrete. The additional usefullness of the hardened biquette ash can be found in contributing toward the solving the various pollution problems, the saving the labor costs needed to clean-up waste materials, and the saving the construction materials.

• Cross-Cultural Studies
• /
• v.43
• /
• pp.265-288
• /
• 2016

This essay begins by discussing the issue of the definition of a catastrophe as a trauma by visual media and the problems that result. We assume a concrete approach towards these problems by examining the process through which 9/11 was defined as a "national trauma" in the exclusion of images of bodies falling from towers, which were some of the most shocking images in the media coverage of 9/11. The choice to exclude images of falling men from American visual media representations of 9/11 goes hand in hand with the tendencies of a contemporary trauma theory. This essay assumes that the representations in the U.S visual media depend on "antimimetic theory," one of the leading contemporary trauma theories, in order to validate its logic, and examines the limitations and problems of the theory. This work aims to examine the issue of the definition of a catastrophe as trauma by visual media on the basis on the "antimimetic theory" and the danger that results. Because the antimimetic theory, which the visual media in the United States uses to define 9/11 as trauma, emphasizes literal and unmediated representation of an external event, it lacks an understanding of the human aspects of the event. There is no way to intervene in the construction and interpretation of the trauma. As a result, the theory discourages active attempts to find a solution to the problems of the people directly connected with the event. Thus, it provides an opening for manipulative intervention of an external power. This essay attempts to provide a critical analysis of the "antimimetic theory" in order to help people who witness catastrophic events through various types of visual media, and to seek an alternative means of experiencing and responding to the trauma, that does not stem from the perspective of specific media outlets or external powers.

• The Korean Journal of Archival Studies
• /
• no.5
• /
• pp.39-85
• /
• 2002

This paper is aimed at proposing the policies for managing archives in the process of promoting Electronic Government System. Although there have been many studies of electronic government project and plans for its establishment, this research examines the electronic government system and its problems on the basis of archival science. What I acquired in this paper is as follows. The development of information technology needs great changes ranging from the nation to the individuals. It becomes common that the use of computerized program for business purposes, computerization of information materials and the effective way of search use of electronic documents. Therefore, more and more countries all over the world have been seeking to promote 'Electronic Government', which applies the fruits of the development in information technology to administration process. Recently, Korea has been rapidly entered into the 'Electronic Government' system being against the traditional way of administration. In electronic government system, the 'Life Cycle' of public records will be computerized. Therefore, it is important to change and develop along with the government's policies for 'electronic government project' in the archival management system. This means that the archival management system which have put emphasis on the textual records should be converted to electronic records system. In other words, the records management in electronic government system requires not the transfer and preservation of the records but the consistent management system including the whole process of creating, appraising, arranging, preserving and using the records. So, the systematic management of electronic records plays an important role in realization of electronic government, but it is a subject to be realized by electronic government at the same time. However, the government have overlooked the importance of archival management for long time, especially the importance of electronic records management system. First of all, this research attempts to infer limits and problems through the theoretical considerations of the existing studies for electronic government and to clear up the relations between electronic government and archival management. Based on this, I'll seek to progress the study through reviewing the present condition of archival management in the process of promoting electronic government and suggesting the policies for enhancing the successful electronic government and the construction of scientific archival management system. Since early 1990, many countries in the world have been making every effort to concrete 'Electronic Government'. Using the examples in other nations, it is not difficult to recognize that the embodiment of electronic government is closely connected with the archival management policies. Korea have completed legal and institutional equipments including the new establishment of "Electronic Government Law" to realize electronic government. Also, Korea has been promoting electronic government with the Ministry of Government Administration and Home Affairs and Government Computer Center as a leaders. Though managing records, especially the management of electronic records is essential in electronic government system, we haven't yet discussed this section in Korea. This is disapproved by the fact the Government Archives and Records Service has played little role in promoting electronic government project. There are two problems relating this environment. First, present system can't meet the consistent 'Life Cycle' ranging from the creation to the preservation of electronic records. Second, the 'Life Cycle' of electronic records is divided into two parts and managed separately by GCC and GARS. The life of records is not end with the process raged from creation to distribution. On the other hand, the records are approved their value only whole procedures. Therefore, GARS should play a deading role in designing and establishing the archival management system. The answer to these problems, is as follows. First, we have to complete the electronic records management system through introducing ERMS not EDMS. This means that we should not change and develop towards ERMS simply with supplementing the current electronic records management system. I confirm that it is important and proper to establish ERMS system from the very beginning of the process of promoting electronic government. Second, I suggest the developmental integration of GARS and GCC. At present, the divided operations of GCC and GARS, the former is in charge of the management center for electronic business and the latter is the hub institution of managing nation's records and archives result in many obstacles in establishing electronic government system and accomplishing the duties of systematic archival management. Therefore, I conclude that the expansive movement towards 'National Archives' through the integration among the related agencies will make a great contribution to the realization of electronic government and the establishment of archival management system. In addition to this, it will be of much help to constitute and operate the 'Task Force' regarding the management of electronic records with the two institution as the central figures.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.47 no.3
• /
• pp.1-11
• /
• 2019

The purpose of this study is to propose a sustainable village-unit urban regeneration plan for the Ewha Mural Village, where mural artists recovered concrete fences to be followed by some residents damaging the mural paintings. Through a review of the existing literature and a preliminary survey, we derived the urban regeneration factors (environmental sustainability, economic sustainability, and social sustainability) applicable at the village level. After an empirical survey on the residents, we tried to identify various problems of the Ewha Mural Village. Residents selected the factors of accessibility, parking management, diversity of industries, creation of new jobs, community participation of residents for the mural village's activation, and stable living spaces. In the case of Ewha Mural Village, physical environment factors for the residents at the time of construction were not considered and the village was mainly planned using budget-based murals. Since then, the inequality of economic benefits intensified the conflicts among the residents. In addition, public benefits, such as establishing new industries and employing outsiders, were not provided, and these facts appear to have led to an unsustainable murals village, in which the murals that are the protagonists of the village revitalization are being destroyed. Therefore, the urban regeneration of Ewha Mural Village should be designed considering a region where some residential areas can be transformed into tourist areas. In addition, it is essential to employ a win-win method to improve the living environment, such as road maintenance, not only partial economic benefits, such as increased land-value, and to increase resident's value as a common asset within the village itself.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.3A
• /
• pp.201-209
• /
• 2010

Generally, PSC girder bridge uses total gross cross section to resist applied loads unlike reinforced concrete member. Also, it is used as short and middle span (less than 30 m) bridges due to advantages such as ease of design and construction, reduction of cost, and convenience of maintenance. But, due to recent increased public interests for environmental friendly and appearance appealing bridges all over the world, the demands for longer span bridges have been continuously increasing. This trend is shown not only in ordinary long span bridge types such as cable supported bridges but also in PSC girder bridges. In order to meet the increasing demands for new type of long span bridges, PSC hollow box girder with H-type steel as compression reinforcements is developed for bridge with a single span of more than 50 m. The developed PSC girder applies compressive prestressing at H-type compression reinforcements using unbonded PS tendon. The purpose of compressive prestressing is to recover plastic displacement of PSC girder after long term service by releasing the prestressing. The static test composed of 4 different stages in 3-point bending test is performed to verify safety of the bridge. First stage loading is applied until tensile cracks form. Then in second stage, the load is removed and the girder is unloaded. In third stage, after removal of loading, recovery of remaining plastic deformation is verified as the compressive prestressing is removed at H-type reinforcements. Then, in fourth stage, loading is continued until the girder fails. The experimental results showed that the first crack occurs at 1,615 kN with a corresponding displacement of 187.0 mm. The introduction of the additional compressive stress in the lower part of the girder from the removal of unbonded compressive prestressing of the H-type steel showed a capacity improvement of about 60% (7.7 mm) recovery of the residual deformation (18.7 mm) that occurred from load increase. By using prestressed H-type steel as compression reinforcements in the upper part of cross section, repair and rehabilitation of PSC girders are relatively easy, and the cost of maintenance is expected to decrease.

• Economic and Environmental Geology
• /
• v.57 no.2
• /
• pp.161-175
• /
• 2024

Aggregate typically refers to sand and gravel formed by the transportation of rocks in rivers or artificially crushed, constituting a core resource in the construction industry. Gyeongsangbuk-do, the largest administrative area in South Korea, produces various sources of gravel, including forest, land (excluding other sources), river, and crushed stone. As of 2022, it has extracted approximately 6.96 million cubic meters of aggregate, with permitted production totaling around 4.07 million cubic meters and reported production of about 2.88 million cubic meters. The aggregate demand in Gyeongsangbuk-do is estimated to be 12.39 million cubic meters according to the estimation method in Ready-Mix Concrete. From the supply perspective, about 120 extraction sites are operational, with most municipalities maintaining an appropriate balance between aggregate demand and supply. However, in some areas, there is inbound and outbound transportation of aggregate to neighboring regions. Regions with significant inbound and outbound aggregate transportation in Gyeongsangbuk-do are areas connected to Daegu Metropolitan City and Pohang City along the Gyeongbu rail line, showing a high correlation with population distribution. Gyeongsangbuk-do faces challenges such as population decline, aging rural areas, and insufficient balanced regional development. Analysis using GIS reveals these trends in gravel demand and supply. Currently in this study, Gyeongsangbuk-do meets its demand for aggregate through the supply of various aggregate sources, maintaining stable aggregate procurement. River and terrestrial aggregates may be sustained as short-term supply strategies due to the difficulty of longterm development. Considering the reliance on raw material supply for selective crushing, it suggests the need for raw material management to maintain stability. Gyeongsangbuk-do highlights quarries in the forest as an important resource for sustainable aggregate supply, advocating for the development of large-scale aggregate quarries as a long-term alternative. These research findings are expected to provide valuable insights for formulating strategies for sustainable management and stable utilization of aggregate resources.

• Journal of Intelligence and Information Systems
• /
• v.25 no.2
• /
• pp.167-194
• /
• 2019

This research starts from the four basic concepts of incentive incompatibility, limited information, myopia and decision variable which are confronted when making decisions in keyword bidding. In order to make these concept concrete, four framework approaches are designed as follows; Strategic approach for the incentive incompatibility, Statistical approach for the limited information, Alternative optimization for myopia, and New model approach for decision variable. The purpose of this research is to propose the statistical optimization model in constructing the portfolio of Sponsored Search Advertising (SSA) in the Sponsor's perspective through empirical tests which can be used in portfolio decision making. Previous research up to date formulates the CTR estimation model using CPC, Rank, Impression, CVR, etc., individually or collectively as the independent variables. However, many of the variables are not controllable in keyword bidding. Only CPC and Rank can be used as decision variables in the bidding system. Classical SSA model is designed on the basic assumption that the CPC is the decision variable and CTR is the response variable. However, this classical model has so many huddles in the estimation of CTR. The main problem is the uncertainty between CPC and Rank. In keyword bid, CPC is continuously fluctuating even at the same Rank. This uncertainty usually raises questions about the credibility of CTR, along with the practical management problems. Sponsors make decisions in keyword bids under the limited information, and the strategic portfolio approach based on statistical models is necessary. In order to solve the problem in Classical SSA model, the New SSA model frame is designed on the basic assumption that Rank is the decision variable. Rank is proposed as the best decision variable in predicting the CTR in many papers. Further, most of the search engine platforms provide the options and algorithms to make it possible to bid with Rank. Sponsors can participate in the keyword bidding with Rank. Therefore, this paper tries to test the validity of this new SSA model and the applicability to construct the optimal portfolio in keyword bidding. Research process is as follows; In order to perform the optimization analysis in constructing the keyword portfolio under the New SSA model, this study proposes the criteria for categorizing the keywords, selects the representing keywords for each category, shows the non-linearity relationship, screens the scenarios for CTR and CPC estimation, selects the best fit model through Goodness-of-Fit (GOF) test, formulates the optimization models, confirms the Spillover effects, and suggests the modified optimization model reflecting Spillover and some strategic recommendations. Tests of Optimization models using these CTR/CPC estimation models are empirically performed with the objective functions of (1) maximizing CTR (CTR optimization model) and of (2) maximizing expected profit reflecting CVR (namely, CVR optimization model). Both of the CTR and CVR optimization test result show that the suggested SSA model confirms the significant improvements and this model is valid in constructing the keyword portfolio using the CTR/CPC estimation models suggested in this study. However, one critical problem is found in the CVR optimization model. Important keywords are excluded from the keyword portfolio due to the myopia of the immediate low profit at present. In order to solve this problem, Markov Chain analysis is carried out and the concept of Core Transit Keyword (CTK) and Expected Opportunity Profit (EOP) are introduced. The Revised CVR Optimization model is proposed and is tested and shows validity in constructing the portfolio. Strategic guidelines and insights are as follows; Brand keywords are usually dominant in almost every aspects of CTR, CVR, the expected profit, etc. Now, it is found that the Generic keywords are the CTK and have the spillover potentials which might increase consumers awareness and lead them to Brand keyword. That's why the Generic keyword should be focused in the keyword bidding. The contribution of the thesis is to propose the novel SSA model based on Rank as decision variable, to propose to manage the keyword portfolio by categories according to the characteristics of keywords, to propose the statistical modelling and managing based on the Rank in constructing the keyword portfolio, and to perform empirical tests and propose a new strategic guidelines to focus on the CTK and to propose the modified CVR optimization objective function reflecting the spillover effect in stead of the previous expected profit models.