• Title/Summary/Keyword: Maximum efficiency

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A Study on the Meaning and Strategy of Keyword Advertising Marketing

  • Park, Nam Goo
    • Journal of Distribution Science
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    • v.8 no.3
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    • pp.49-56
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    • 2010
  • At the initial stage of Internet advertising, banner advertising came into fashion. As the Internet developed into a central part of daily lives and the competition in the on-line advertising market was getting fierce, there was not enough space for banner advertising, which rushed to portal sites only. All these factors was responsible for an upsurge in advertising prices. Consequently, the high-cost and low-efficiency problems with banner advertising were raised, which led to an emergence of keyword advertising as a new type of Internet advertising to replace its predecessor. In the beginning of 2000s, when Internet advertising came to be activated, display advertisement including banner advertising dominated the Net. However, display advertising showed signs of gradual decline, and registered minus growth in the year 2009, whereas keyword advertising showed rapid growth and started to outdo display advertising as of the year 2005. Keyword advertising refers to the advertising technique that exposes relevant advertisements on the top of research sites when one searches for a keyword. Instead of exposing advertisements to unspecified individuals like banner advertising, keyword advertising, or targeted advertising technique, shows advertisements only when customers search for a desired keyword so that only highly prospective customers are given a chance to see them. In this context, it is also referred to as search advertising. It is regarded as more aggressive advertising with a high hit rate than previous advertising in that, instead of the seller discovering customers and running an advertisement for them like TV, radios or banner advertising, it exposes advertisements to visiting customers. Keyword advertising makes it possible for a company to seek publicity on line simply by making use of a single word and to achieve a maximum of efficiency at a minimum cost. The strong point of keyword advertising is that customers are allowed to directly contact the products in question through its more efficient advertising when compared to the advertisements of mass media such as TV and radio, etc. The weak point of keyword advertising is that a company should have its advertisement registered on each and every portal site and finds it hard to exercise substantial supervision over its advertisement, there being a possibility of its advertising expenses exceeding its profits. Keyword advertising severs as the most appropriate methods of advertising for the sales and publicity of small and medium enterprises which are in need of a maximum of advertising effect at a low advertising cost. At present, keyword advertising is divided into CPC advertising and CPM advertising. The former is known as the most efficient technique, which is also referred to as advertising based on the meter rate system; A company is supposed to pay for the number of clicks on a searched keyword which users have searched. This is representatively adopted by Overture, Google's Adwords, Naver's Clickchoice, and Daum's Clicks, etc. CPM advertising is dependent upon the flat rate payment system, making a company pay for its advertisement on the basis of the number of exposure, not on the basis of the number of clicks. This method fixes a price for advertisement on the basis of 1,000-time exposure, and is mainly adopted by Naver's Timechoice, Daum's Speciallink, and Nate's Speedup, etc, At present, the CPC method is most frequently adopted. The weak point of the CPC method is that advertising cost can rise through constant clicks from the same IP. If a company makes good use of strategies for maximizing the strong points of keyword advertising and complementing its weak points, it is highly likely to turn its visitors into prospective customers. Accordingly, an advertiser should make an analysis of customers' behavior and approach them in a variety of ways, trying hard to find out what they want. With this in mind, her or she has to put multiple keywords into use when running for ads. When he or she first runs an ad, he or she should first give priority to which keyword to select. The advertiser should consider how many individuals using a search engine will click the keyword in question and how much money he or she has to pay for the advertisement. As the popular keywords that the users of search engines are frequently using are expensive in terms of a unit cost per click, the advertisers without much money for advertising at the initial phrase should pay attention to detailed keywords suitable to their budget. Detailed keywords are also referred to as peripheral keywords or extension keywords, which can be called a combination of major keywords. Most keywords are in the form of texts. The biggest strong point of text-based advertising is that it looks like search results, causing little antipathy to it. But it fails to attract much attention because of the fact that most keyword advertising is in the form of texts. Image-embedded advertising is easy to notice due to images, but it is exposed on the lower part of a web page and regarded as an advertisement, which leads to a low click through rate. However, its strong point is that its prices are lower than those of text-based advertising. If a company owns a logo or a product that is easy enough for people to recognize, the company is well advised to make good use of image-embedded advertising so as to attract Internet users' attention. Advertisers should make an analysis of their logos and examine customers' responses based on the events of sites in question and the composition of products as a vehicle for monitoring their behavior in detail. Besides, keyword advertising allows them to analyze the advertising effects of exposed keywords through the analysis of logos. The logo analysis refers to a close analysis of the current situation of a site by making an analysis of information about visitors on the basis of the analysis of the number of visitors and page view, and that of cookie values. It is in the log files generated through each Web server that a user's IP, used pages, the time when he or she uses it, and cookie values are stored. The log files contain a huge amount of data. As it is almost impossible to make a direct analysis of these log files, one is supposed to make an analysis of them by using solutions for a log analysis. The generic information that can be extracted from tools for each logo analysis includes the number of viewing the total pages, the number of average page view per day, the number of basic page view, the number of page view per visit, the total number of hits, the number of average hits per day, the number of hits per visit, the number of visits, the number of average visits per day, the net number of visitors, average visitors per day, one-time visitors, visitors who have come more than twice, and average using hours, etc. These sites are deemed to be useful for utilizing data for the analysis of the situation and current status of rival companies as well as benchmarking. As keyword advertising exposes advertisements exclusively on search-result pages, competition among advertisers attempting to preoccupy popular keywords is very fierce. Some portal sites keep on giving priority to the existing advertisers, whereas others provide chances to purchase keywords in question to all the advertisers after the advertising contract is over. If an advertiser tries to rely on keywords sensitive to seasons and timeliness in case of sites providing priority to the established advertisers, he or she may as well make a purchase of a vacant place for advertising lest he or she should miss appropriate timing for advertising. However, Naver doesn't provide priority to the existing advertisers as far as all the keyword advertisements are concerned. In this case, one can preoccupy keywords if he or she enters into a contract after confirming the contract period for advertising. This study is designed to take a look at marketing for keyword advertising and to present effective strategies for keyword advertising marketing. At present, the Korean CPC advertising market is virtually monopolized by Overture. Its strong points are that Overture is based on the CPC charging model and that advertisements are registered on the top of the most representative portal sites in Korea. These advantages serve as the most appropriate medium for small and medium enterprises to use. However, the CPC method of Overture has its weak points, too. That is, the CPC method is not the only perfect advertising model among the search advertisements in the on-line market. So it is absolutely necessary that small and medium enterprises including independent shopping malls should complement the weaknesses of the CPC method and make good use of strategies for maximizing its strengths so as to increase their sales and to create a point of contact with customers.

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Comparison and evaluation between 3D-bolus and step-bolus, the assistive radiotherapy devices for the patients who had undergone modified radical mastectomy surgery (변형 근치적 유방절제술 시행 환자의 방사선 치료 시 3D-bolus와 step-bolus의 비교 평가)

  • Jang, Wonseok;Park, Kwangwoo;Shin, Dongbong;Kim, Jongdae;Kim, Seijoon;Ha, Jinsook;Jeon, Mijin;Cho, Yoonjin;Jung, Inho
    • The Journal of Korean Society for Radiation Therapy
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    • v.28 no.1
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    • pp.7-16
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    • 2016
  • Purpose : This study aimed to compare and evaluate between the efficiency of two respective devices, 3D-bolus and step-bolus when the devices were used for the treatment of patients whose chest walls were required to undergo the electron beam therapy after the surgical procedure of modified radical mastectomy, MRM. Materials and Methods : The treatment plan of reverse hockey stick method, using the photon beam and electron beam, had been set for six breast cancer patients and these 6 breast cancer patients were selected to be the subjects for this study. The prescribed dose of electron beam for anterior chest wall was set to be 180 cGy per treatment and both the 3D-bolus, produced using 3D printer(CubeX, 3D systems, USA) and the self-made conventional step-bolus were used respectively. The surface dose under 3D-bolus and step-bolus was measured at 5 measurement spots of iso-center, lateral, medial, superior and inferior point, using GAFCHROMIC EBT3 film (International specialty products, USA) and the measured value of dose at 5 spots was compared and analyzed. Also the respective treatment plan was devised, considering the adoption of 3D-bolus and stepbolus and the separate treatment results were compared to each other. Results : The average surface dose was 179.17 cGy when the device of 3D-bolus was adopted and 172.02 cGy when step-bolus was adopted. The average error rate against the prescribed dose of 180 cGy was -(minus) 0.47% when the device of 3D-bolus was adopted and it was -(minus) 4.43% when step-bolus was adopted. It was turned out that the maximum error rate at the point of iso-center was 2.69%, in case of 3D-bolus adoption and it was 5,54% in case of step-bolus adoption. The maximum discrepancy in terms of treatment accuracy was revealed to be about 6% when step-bolus was adopted and to be about 3% when 3D-bolus was adopted. The difference in average target dose on chest wall between 3D-bolus treatment plan and step-bolus treatment plan was shown to be insignificant as the difference was only 0.3%. However, to mention the average prescribed dose for the part of lung and heart, that of 3D-bolus was decreased by 11% for lung and by 8% for heart, compared to that of step-bolus. Conclusion : It was confirmed through this research that the dose uniformity could be improved better through the device of 3D-bolus than through the device of step-bolus, as the device of 3D-bolus, produced in consideration of the contact condition of skin surface of chest wall, could be attached to patients' skin more nicely and the thickness of chest wall can be guaranteed more accurately by the device of 3D-bolus. It is considered that 3D-bolus device can be highly appreciated clinically because 3D-bolus reduces the dose on the adjacent organs and make the normal tissues protected, while that gives no reduction of dose on chest wall.

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Studies on the growth of Korea Lawn Grass (Zoysia japonica Steud.)in Reponse to Nitrogen Application, Clipping Treatment and Plant Density (질소시용, 예초 및 재식밀도가 한국잔디(Zoysia Japonica Steud)의 생육에 미치는 영향)

  • Sim, Jae-Seong
    • The Journal of Natural Sciences
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    • v.1
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    • pp.61-113
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    • 1987
  • The increasing emphasis placed on the production of fine turf for lawns, golf courses, parks, and other recreational sites has led to many unsolved problems as to how such turf could be best established and mainteined. For this purpose, a series of experiments were conducted under con ditions of pot and field. The results obtained were as follows EXPERIMENT I. The effect of nitrogen fertilizer and clipping interval on Zoysia japonica. 1. Increasing the rate of nitrogen and frequent clipping increased tiller number of Zoysis japonica and the maximum number of tillers were obtained from 700 kg N application and freqnent clippings (10 days interval ) in October. Treatment of 350kg N with 10 days clipping interval increased tillers much more than those of 700 kgN with 20 and 30 days clipping intervals. 2. The average number of green leaves occurred during the growth period maximized by applying 700 kg N and clipping 10 days interval. 3. Increasing tiller numbers significantly decreased tops DM weight per tiller by clipping plants at interval of 10 and 20 days, irrespective of nitrogen applied, and with nil N, at the interval of 30 days. By applying 700 kg N, however, top DM weight per tiller increased as the number of tillers increased consistently. 4. The highest top DM weight was achieved from late August to early September by applying 350 and 700kgN. 5. During the growth period, differences in unders ( stolon + root ) DM weight occurred bynitrogen application were found between nil N and two applied nitrogen levels, whereas, at the same level of nitrogen applied, the increase in stolon DM weight enhanced by lengthening the clipping interval to 30 days. 6. Nitrogen efficiency to green leaves, stolon nodes and DM weight of root with high nitrogen was achieved as clipping interval was shortened. 7. By increasing fertilizer nitrogen rate applied, N content n the leaves and stems of Zoysiajaponica was increased. On the other hand, N content in root and stolon had little effect onfertilizer nitrogen, resulting in the lowest content among plant fractions. The largest content of N was recorded in leaves. Lengthening the clipping interval from 10 or 20 to 30 days tends to decrease the N content in the leaves and stems, whereas this trend did not appeared in stolon androot. 8. A positive correlations between N and K contents in tops and stolon were established andthus K content increased as N content in tops and stolon increased. Meanwhile, P content was not affected by N and clipping treatments. 9. Total soluble carbohydrate content in Zoysia japonica was largest in stolon and stem, and was reduced by increasing fertilizer nitrogen rate. Reduction in total soluble carbohydrate due to increased nitrogen rate was severer in the stolons and stems than in the leaves. 10. Increasing the rate of nitrogen applied increased the number of small and large vascular bundles in leaf blade, but shortened distance among the large vascular bundles. Shortening the clipping interval resulted in increase of the number of large vascular bundles but decrease ofdistance between large vascular bundles.EXPERIMENT II. Growth response of Zoysia japonica imposed by different plant densities. 1. Tiller numbers per unit area increased as plant density heightened. Differences in num ber between densities at higher densities than 120 D were of no significance. 2. Tiller numbers per clone attained by 110 days after transplanting were 126 at 40D,77 at 80D, 67 at 120D, 54 at 160D, and 41 at 200D. A decreasing trend of tiller numbers per clone with increasing density was noticable from 100 days after transplanting onwards. 3. During the growth period, the greatest number of green leaves per unit area were attainedin 90days after transplanting at 160D and 200D, and 100 days after transplanting at 40D, 80Dand 120D. Thus the period to reach the maximum green leaf number with the high plantdensity was likely to be earlier that with the low plant density. 4. Stolon growth up to 80 days after transplaning was relatively slow, but from 80 daysonwards, the growth quickened to range from 1.9 m/clone at 40D to 0.6m/clone at 200Din 200 days after transplanting, these followed by the stolon node produced. 5. Plant density did not affect stolon weight/clone and root weight/clone until 80 daysafter transplanting. 6. DM weight of root was heavier in the early period of growth than that of stolon, butthis trend was reversed in the late period of growth : DM weight of stolon was much higherthan that of root.EXPERIMENT Ill. Vegetative growth of Zoysia japonica and Zoysia matrella as affected by nitrogen and clipping height. 1. When no nitrogen was applied to Zoysia japonica, leaf blade which appeared during theAugust-early September period remained green for a perid of about 10 weeks and even leavesemerged in rate September lived for 42 days. However, leaf longevity did not exceed 8 weeks asnitrogen was applied. In contrast the leaf longevity of Zoysia matrella which emerged during the mid August-earlySeptember period was 11 weeks and, under the nitrogen applied, 9 weeks, indicating that thelife-spen of individual leaf of Zoysia matrella may be longer than that of Zoysia japorica. Clipping height had no effect on the leaf longevity in both grasses. 2. During the July-August period, tiller number, green leaf number and DM weightof Zoysia japonica were increased significantly with fertilizer nitrogen, but were not with twolevel of clipping height. This trend was reversed after late September ; no effect of nitrogen wasappeared. Instead, lax clipping increased tiller number, green leaf number and DM weight. Greenleaves stimulated by lax clipping resulted in the occurrance of more dead leaves in late October. 3. Among the stolons outgrown until early September, the primary stolon was not influencedby nitrogen and clipping treatments to produce only 2-3 stolons. However, 1st branch stoIon asaffected by nitrogen increased significantly, so most of stolons which occurred consisted of 1st branch stolons. 4. Until early September, stolon length obtained at nil nitrogen level was chiefly caused bythe primary stolons. By applying nitrogen, the primary stolons of Zoysia japonica waslonger than 1st branch stolons when severe clipping was involved and in turn, shorter than 1stbranch stolons when lax clipping was concerned. In Zoysia matrella, 1st branch stolons were muchlonger than the primary stolon when turf was clipped severely but in conditions of lax clippingthere was little difference in length between primary and 1st branch stolons. 5. Stolon nodes of both Zoysia japonica and Z. matrella were positively influenced by nit rogen, but no particular increase by imposing clipping height treatment was marked in Zoysiamatrella. Although the stolon of Zoysia japonica grew until late October, the growthstimulated by nitrogen was not so remarkable as to exceed that by nil N.

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Performance analysis of Frequent Itemset Mining Technique based on Transaction Weight Constraints (트랜잭션 가중치 기반의 빈발 아이템셋 마이닝 기법의 성능분석)

  • Yun, Unil;Pyun, Gwangbum
    • Journal of Internet Computing and Services
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    • v.16 no.1
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    • pp.67-74
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    • 2015
  • In recent years, frequent itemset mining for considering the importance of each item has been intensively studied as one of important issues in the data mining field. According to strategies utilizing the item importance, itemset mining approaches for discovering itemsets based on the item importance are classified as follows: weighted frequent itemset mining, frequent itemset mining using transactional weights, and utility itemset mining. In this paper, we perform empirical analysis with respect to frequent itemset mining algorithms based on transactional weights. The mining algorithms compute transactional weights by utilizing the weight for each item in large databases. In addition, these algorithms discover weighted frequent itemsets on the basis of the item frequency and weight of each transaction. Consequently, we can see the importance of a certain transaction through the database analysis because the weight for the transaction has higher value if it contains many items with high values. We not only analyze the advantages and disadvantages but also compare the performance of the most famous algorithms in the frequent itemset mining field based on the transactional weights. As a representative of the frequent itemset mining using transactional weights, WIS introduces the concept and strategies of transactional weights. In addition, there are various other state-of-the-art algorithms, WIT-FWIs, WIT-FWIs-MODIFY, and WIT-FWIs-DIFF, for extracting itemsets with the weight information. To efficiently conduct processes for mining weighted frequent itemsets, three algorithms use the special Lattice-like data structure, called WIT-tree. The algorithms do not need to an additional database scanning operation after the construction of WIT-tree is finished since each node of WIT-tree has item information such as item and transaction IDs. In particular, the traditional algorithms conduct a number of database scanning operations to mine weighted itemsets, whereas the algorithms based on WIT-tree solve the overhead problem that can occur in the mining processes by reading databases only one time. Additionally, the algorithms use the technique for generating each new itemset of length N+1 on the basis of two different itemsets of length N. To discover new weighted itemsets, WIT-FWIs performs the itemset combination processes by using the information of transactions that contain all the itemsets. WIT-FWIs-MODIFY has a unique feature decreasing operations for calculating the frequency of the new itemset. WIT-FWIs-DIFF utilizes a technique using the difference of two itemsets. To compare and analyze the performance of the algorithms in various environments, we use real datasets of two types (i.e., dense and sparse) in terms of the runtime and maximum memory usage. Moreover, a scalability test is conducted to evaluate the stability for each algorithm when the size of a database is changed. As a result, WIT-FWIs and WIT-FWIs-MODIFY show the best performance in the dense dataset, and in sparse dataset, WIT-FWI-DIFF has mining efficiency better than the other algorithms. Compared to the algorithms using WIT-tree, WIS based on the Apriori technique has the worst efficiency because it requires a large number of computations more than the others on average.

Cyclic Seismic Performance of RBS Weak-Axis Welded Moment Connections (RBS 약축 용접모멘트접합부의 내진성능 평가)

  • Lee, Cheol Ho;Jung, Jong Hyun;Kim, Sung Yong
    • Journal of Korean Society of Steel Construction
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    • v.27 no.6
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    • pp.513-523
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    • 2015
  • In steel moment frames constructed of H-shapes, strong-axis moment connections should be used for maximum structural efficiency if possible. And most of cyclic seismic testing, domestic and international, has been conducted for strong-axis moment connections and cyclic test data for weak-axis connections is quite limited. However, when perpendicular moment frames meet, weak-axis moment connections are also needed at the intersecting locations. Especially, both strong- and weak-axis moment connections have been frequently used in domestic practice. In this study, cyclic seismic performance of RBS (reduced beam section) weak-axis welded moment connections was experimentally investigated. Test specimens, designed according to the procedure proposed by Gilton and Uang (2002), performed well and developed an excellent plastic rotation capacity of 0.03 rad or higher, although a simplified sizing procedure for attaching the beam web to the shear plate in the form of C-shaped fillet weld was used. The test results of this study showed that the sharp corner of C-shaped fillet weld tends to be the origin of crack propagation due to stress concentration there and needs to be trimmed for the better weld shape. Different from strong-axis moment connections, due to the presence of weld access hole, a kind of CJP butt joint is formed between the beam flange and the horizontal continuity plate in weak-axis moment connections. When weld access hole is large, this butt joint can experience cyclic local buckling and subsequent low cycle fatigue fracture as observed in this testing program. Thus the size of web access hole at the butt joint should be minimized if possible. The recommended seismic detailing such as stickout, trimming, and thicker continuity plate for construction tolerance should be followed for design and fabrication of weak-axis welded moment connections.

Growth of Kale Seedlings Affected by the Control of Light Quality and Intensity under Smart Greenhouse Conditions with Artificial Lights (인공광 스마트온실에서 광질 및 광강도 제어가 케일 실생묘의 생장에 미치는 영향)

  • Heo, Jeong-Wook;Lee, Jae-Su;Lee, Gong-In;Kim, Hyun-Hwan
    • Korean Journal of Environmental Agriculture
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    • v.36 no.3
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    • pp.193-200
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    • 2017
  • BACKGROUND: Plant growth under smart greenhouse (that is plant factory system) conditions of an artificial light type is significantly depending on the artificial light sources such as a fluorescent lamps or Light-Emitting Diodes (LEDs) with specific spectral wavelengths regardless of the outside environmental changes. In this experiment, characteristics on the growth and compound synthesis of kale seedlings affected by light qualities and intensities provided by LEDs were mentioned. METHODS AND RESULTS: The kale seedlings which developed 3~4 true leaves were exposed by fluorescent lamps or LEDs lights of red (R), blue+white (BW), blue+red (BR) with 50 (L) or $100(H){\mu}mol/m^2/s^1$ photosynthetic photon flux (PPF) under hydroponic culture system of deep flow technique for 50 days. Shoot fresh weight increased under the RH, BWH, and BRH treatments with higher PPF. Shoot elongation of the seedlings decreased, and polyphenol synthesis promoted by the higher light intensity conditions. Sugar synthesis in the leaves was above 2 times greater under the RH treatment of monochromic red light quality with $100{\mu}mol/m^2/s^1\;PPF$ than $50{\mu}mol/m^2/s^1\;PPF$. CONCLUSION: The results show that the control of light quality and intensity in the smart greenhouse conditions with artificial lights significantly affects the growth and compound synthesis in the fresh kale leaves with higher culture efficiency compared to the conventional soil culture under greenhouse or field conditions. Researches on the optimum light intensities of the LEDs with special spectral wavelengths are necessary for maximum growth and metabolism in the seedlings.

Economic Rationale of Compensating Balance Requirements and Its Impact on Money Supply (「꺾기」의 경제학(經濟學)과 통화량(通貨量) 효과분석(效果分析))

  • Jwa, Sung-hee
    • KDI Journal of Economic Policy
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    • v.14 no.1
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    • pp.89-119
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    • 1992
  • This paper purports to analyze the economic rationale of compensating balance requirements and its impact on money supply. This practice has recently been severely criticized for artificially increasing the money supply and, therefore, limiting the nation's aggregate lending policy under the tight constraint of the given money supply target. A review of the existing literature implies that compensating balance requirements is a banking practice which leads to corrections in the distortion of financial resource allocation due to the imperfection of financial market stemming from asymmetric information and/or financial regulations on deposit and lending rates. Therefore, the economic rationale of this practice is deemed to improve the efficiency of financial resource allocation. On the other hand, the macroeconomic impact of compensating balance requirements on the money supply depends on the impact on the money multiplier, which in turn depends on the desired ratio of deposit that people wish to maintain on the money borrowed from the banking system, and on the desired reserve ratio that the banking system would like to hold for deposit withdrawal. If the compensating balance requirements could increase the desired ratio of deposit to borrowing (bank lending), it will increase the available amount of total reserve within the banking system and, in turn, the money multiplier. However, this channel has not been fully analyzed in the literature, and the direction of the effect is ambiguous. If the practice could reduce the turn-over rate of deposit and, thereby, reduce the desired reserve ratio of the banking system, then it will also increase the money multiplier. While this channel operates unambiguously toward increasing the money multiplier, this effect will be limited by the extent that the banking system holds the excess reserve over the required reserve because the excess reserve will set the maximum amount for the desired reserve to fall. This paper tries to determine the effect on the money supply by empirically estimating the multiplier and the desired ratio of deposit to lending equations as functions of the ratio of compensating balance to the related lending, which is not observable and is estimated for the regression purpose. The results suggest that the effect of compensating balance requirements on the money supply in Korea does not exist or is very tenuous even if it could operate. Therefore, this paper concludes that the well publicized policy of cross cancelling the compensating balance and the related lending will not be effective at controlling the money supply and increasing the amount of loans without expanding the money supply.

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A Study on the Intenna Based on PIFA with Multi Element (Mulit Element를 이용한 PIFA 구조의 Intenna에 관한 연구)

  • Lim, Yo-Han;Chang, Ki-Hun;Yoon, Young-Joong;Kim, Yong-Jin;Kim, Young-Eil;Yoon, Ick-Jae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.7
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    • pp.784-795
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    • 2007
  • In this thesis, the Multi element antenna with wideband and enhanced gain characteristic is proposed to operate at both frequency range from 824 MHz to 896 11Hz for the CDMA and frequency range from 908.5 MHz to 914 MHz for the RFID band. The proposed antenna has tile size of $35{\times}15{\times}5mm^3$ in order to put it in the A model of S company and each element of the proposed antenna is folded to obtain the minimum size. To obtain the antenna with wideband and high gain characteristic, the radiator of the antenna is divided into 4 elements. As a result, bandwidth of the proposed antenna become broader and lower center frequency is appeared due to increased and lengthened current path. Moreover, the enhanced gain characteristic is verified because divided element structure that induct uniform current distribution can get increased antenna efficiency. To attain more uniform current distribution, modified structure of the feeding point that can deliver currents directly is designed. The antenna that alters the feeding structure has higher gain value. Each element is folded to increase the current paths considering the current directions to attain the miniaturization of the antenna. To measure the handset antenna, the handset case must be considered. Even though antenna is designed for predicted characteristic, the resonance frequency is shifted and antenna gain is deteriorated at predicted frequency while antenna is set in the handset case. 1.08 GHz of the resonant frequency is determined after frequency shift from 150 MHz to 200 MHz is confirmed and the maximum gain is measured as 3.1 dBi while antenna is not set in the handset. In case handset case is considered, the experimental results show that the impedance bandwidth for VSWR<2 is from 0.824 GHz to 0.936 GHz(110 MHz). This result appears that the proposed antenna can cover both CDMA and RFID band at once. The measured gain is from -3.4 dBi to -0.5 dBi and it has omni-directional pattern practically.

A Study Bioremediation of Tidal Flat by Microorganism in Pilot Scale Test (환경정화 미생물에 의한 갯벌의 생물학적 정화에 대한 파일럿 규모의 연구)

  • Choi, Hye Jin;Han, Young Sun;Park, Doo Hyun;Oh, Bo Young;Hur, Myung Je;Jo, Nam-Gyu;Kim, Young Hee;Kim, Jong-Guk
    • Journal of Life Science
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    • v.24 no.10
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    • pp.1110-1117
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    • 2014
  • Tidal flats are continuously contaminated by human activities. This study assessed the bioremediation efficiency of tidal flat soil using microcosm reactors and microorganisms originating from the tidal area. We screened 135 bacterial strains that produce extracellular enzymes from the tidal area located in the North port of Incheon bay. Two bacterial strains (Pseudoalteromonas sp. and IC35 Halothiobacillus neapolitanus IC_S22) were selected and used in the microcosm reactors, which were specially designed to functionally mimic the ecological conditions of the tidal flats. Pseudoalteromonas sp. IC35 was selected based on its relatively high activity of the enzymes amylase, cellulose, lipase, and protease. Halothiobacillus neapolitanus IC_S22 was selected for oxidation of sulfur. The M1 and M2 microcosm reactors were operated by continuous feeding of seawater under the same conditions, but M2 was first inoculated with Pseudoalteromonas sp. IC35 before the seawater feeding. The initial COD in both the M1 and M2 microcosm reactors was 320 mg/l. The final COD was 21 mg/l (M1) and 7 mg/l (M2). The M3 and M4 microcosm reactors were operated by continuous feeding of seawater under the same conditions, but M4 was first inoculated with H. neapolitanus IC_S22. The initial sulfate concentration in both the M3 and M4 microcosm reactors was 660 mg/l, and the maximum sulfate concentration was 1,360 mg/l (M3) and 1,600 mg/l (M4).

Estimation of the Required Number of Fan Coil Unit for Surplus Solar Energy Recovery of Greenhouse (온실의 잉여 태양에너지 회수용 FCU 소요대수 검토)

  • Yun, Sung-Wook;Choi, Man Kwon;Kim, Ha Neul;Kang, Donghyeon;Lee, Siyoung;Son, Jinkwan;Yoon, Yong Cheol
    • Journal of Bio-Environment Control
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    • v.25 no.2
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    • pp.83-88
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    • 2016
  • In this study, previously reported surplus solar energy-related study result and current status of fan coil unit (FCU) for cooling and heating installed in the current sites were briefly examined and then a method to determine the number of FCUs required to recover surplus solar energy was schematically proposed to provide basic data for researchers and technical engineers in this field. The maximum, mean, and minimum outside temperatures during the experiment period were about $28.2^{\circ}C$, $4.4^{\circ}C$, and $-11.5^{\circ}C$, respectively. The horizontal surface solar radiation level outside the greenhouse was in a range of $0.8-20.5MJ{\cdot}m^{-2}$ and mean and total solar radiation were $10.8MJ{\cdot}m^{-2}$ and $1,187.5MJ{\cdot}m^{-2}$. The mean temperature and relative humidity in the greenhouse during the daytime were in a range of 18.8-45.5 and 53.5-77.5%. The total surplus solar energy recovered from the greenhouse during the experiment period was approximately 6,613.4MJ, which could supplement about 6.7% of the total heating energy 98,600.2 MJ. In addition, the number of FCUs installed for heating varies case to case, although similar FCUs are used. Thus, it is necessary to study the installation height, orientation and installation distance as well as the appropriate number of FCUs from the efficient and economical viewpoints. The required numbers of FCUs for surplus solar energy recovery were 8.4-10.9units and 6.1-8.0units based on air mass and circular flow rate that passed through the FCUs. Considering calculation methods and the risks such as efficiency and use environments of FCUs, it was found that about nine units (one unit per $24m^3$ approximately) needed to be installed. The required number of FCUs for surplus solar energy recovery was around one unit per $24m^3$ approximately.