• Title/Summary/Keyword: $K^{+}$ channels

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Role of $Ca^{2+}$ for Inactivation of N-type Calcium Current in Rat Sympathetic Neurons (흰쥐 교감신경 뉴론 N형 칼슘전류의 비활성화에 미치는 칼슘효과)

  • Goo, Yong-Sook;Keith S. Elmslie
    • Progress in Medical Physics
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    • v.14 no.1
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    • pp.54-67
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    • 2003
  • The voltage-dependence of N-type calcium current inactivation is U-shaped with the degree of inactivation roughly mirroring inward current. This voltage-dependence has been reported to result from a purely voltage-dependent mechanism. However, $Ca^{2+}$-dependent inactivation of N-channels has also been reported. We have investigated the role of $Ca^{2+}$ in N-channel inactivation by comparing the effects of $Ba^{2+}$and $Ca^{2+}$ on whole-cell N-current in rat superior cervical ganglion neurons. For individual cells in-activation was always larger in $Ca^{2+}$ than in $Ba^{2+}$ even when internal EGTA (11 mM) was replaced with BAPTA (20 mM). The inactivation vs. voltage relationship was U-shaped in both divalent cations. The enhancement of inactivation by $Ca^{2+}$ was inversely related with the magnitude of inactivation in $Ba^{2+}$ as if the mechanisms of inactivation were the same in both $Ba^{2+}$ and $Ca^{2+}$. In support of this idea we could separate fast ( ${\gamma}$ ~150 ms) and slow ( ${\gamma}$ ~ 2500 ms) components of inactivation in both $Ba^{2+}$and $Ca^{2+}$ using 5 sec voltage steps. Differential effects were observed on each component with $Ca^{2+}$ enhancing the magnitude of the fast component and the speed of the slow component. The larger amplitude of fast component indicates that the more channels inactivate via this pathway with $Ca^{2+}$ than with $Ba^{2+}$, but the stable time constants support the idea the fast inactivation mechanism is identical in $Ba^{2+}$and $Ca^{2+}$. The results do not support a $Ca^{2+}$-dependent mechanism for fast inactivation. However, the $Ca^{2+}$-induced acceleration of the slowly inactivating component could result from a $Ca^{2+}$-dependent process.

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A Study on Factors Affecting the Sustainability of Industry-University Cooperation: Focusing on the I-U Relationship Strength and Overcoming I-U barrier (산학협력 지속가능성에 영향을 주는 요인에 관한 연구: 산학협력관계강도와 장애의 극복을 중심으로)

  • Hong, Eun-Young;Choi, Jong-in
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.410-422
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    • 2018
  • This paper studies the factors that increase the sustainability of Industry-University cooperation in the current structure of domestic I-U cooperation, which is highly dependent on government support. First, we examine the extent to which the 'I-U Relationship Strength' can be explained by the cumulative 'Experiences of I-U cooperation' and 'Width of various I-U cooperation channels', and the 'I-U cooperation barrier' can be explained by the 'Difference in mutual recognition' and 'Institutional barriers' on sustainability. In addition, the factors that can lower the 'I-U cooperation barrier', such as the 'University administration's efforts' and 'Trust between I-U', are examined. The researchers examined the factors affecting the sustainability of I-U cooperation and the factors affecting 'I-U cooperation barriers' in the 'I-U cooperation technology development projects' of the Ministry of Small & Medium Venture Business and Startups with its long history of domestic I-U cooperation programs. In order to clarify the data of the research sample, a questionnaire survey of organizational units was conducted for all companies participating in the 'I-U cooperation technology development projects' of the Ministry of SMVB and Startups between 2011 and 2015, and the responses of 356 organizations were used. It was found that the greater the 'Width of the I-U cooperation channels', the higher the sustainability and that the greater the 'Institutional barriers', the lower the sustainability. However, through the 'University administration's efforts' and 'Trust between I-U', it is possible to overcome the 'I-U cooperation barrier'. Ultimately, the systematization of Industry-University-Research institute subjects is needed to realize sustainability. In other words, it is necessary to have a linkage program that can broaden the link between industry and universities, that is to broaden the scope of I-U cooperation. Moreover, it is necessary for the government to provide institutional support to promote desirable I-U cooperation policies. Finally, it is essential to change the universities' core organizations in order to improve the level of university administration services.

Effect of $Ca^{2+}$ and $Ca^{2+}-antagonists$ on the Spontaneous Contractions and Electrical Activities of Guinea-pig Stomach (기니피그 위 평활근의 자발적 수축과 전기적 활동에 대한 $Ca^{2+}$$Ca^{2+}$-길항제 영향)

  • Rhie, Sang-Ho;Kim, Ki-Whan
    • The Korean Journal of Physiology
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    • v.21 no.2
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    • pp.241-257
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    • 1987
  • The effects of external $Ca^{2+}$ and $Ca^{2+}-antagonists$ on the spontaneous contractions and electrical activities were investigated in guinea-pig stomach in order to clarify the mechanism for the generation of slow waves. Electrical responses of circular smooth muscle cells were recorded using glass capillary microelectrodes filled with 3 M KCl. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows: 1) The amplitude of spontaneous contractions was maximal at around 2-4 mM $Ca^{2+}$, whereas their frequency was inversely related with external $Ca^{2+}$ within the range of 0.5 to 16 mM $Ca^{2+}$. 2) Verapamil suppressed the amplitude of spontaneous contraction in a dose-dependent manner, while the frequency of spontaneous contractions was almost not changed over the whole concentration of verapamil $(0.01{\sim}5\;mg/l)$. 3) Manganese increased both the amplitude and the frequency of spontaneous contractions dose-dependently in low $Mn^{2+}$ (below 0.05 mM $Mn^{2+}$), while their amplitude and frequency were decreased in high $Mn^{2+}$ (above 0.1 mM $Mn^{2+}$). 4) The ampltude and maximum rate of rise of slow waves were incrased in high $Ca^{2+}$ solution. In $Ca^{2+}-free$ solution, the spontaneous contractions recorded simultaneously with slow waves ceased and tonic contraction ($Ca^{2+}-free$ contracture) was developed in parallel with membrane depolarization and the disappearance of slow waves. 5) Verapamil (1 mg/1) decreased the amplitude and maximum rate of rise of slow waves and it depolarized the membrane by about 6 mV, whereas the frequency of slow waves was not affected by verapamil. 6) Manganese showed different characteristic effects between low and high $Mn^{2+}$ on the slow waves: In low $Mn^{2+}$ (0.05 mM $Mn^{2+}$), the initial rapid increases and the subsequent gradual decreases in three parameters of slow waves (amplitude, rate of rise, and frequency of slow waves) till a new steady state were observed. However, in high $Mn^{2+}$ (0.5 mM $Mn^{2+}$) slow waves disappeared and membrane was depolarized. From the above results, the following conclusions could be made: 1) $Ca^{2+}$ is necessary for a generation of the slow waves, even though it is small amount. 2) Verapamil suppresses the spontaneous contractions of gastric antral strip by the decreases in amplitude and maximum rate of rise of slow waves, while this drug does not block the $Ca^{2+}-channel$ involved in the generation of slow waves. 3) Manganese has dual actions on the $Ca^{2+}-channels$; the $Ca^{2+}-channel$ involved in the generation of slow waves (or Na-Ca exchange system) or the channel for the generation of spike potentials are stimulated by a low concentration of $Mn^{2+}$, while both the $Ca^{2+}$. Channels are blocked by high concentration of $Mn^{2+}$.

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Study on "Four Tantras", the Prime Textbook of Tibetan Medicine (티벳의학에 대한 연구 - "사부의전(四部醫典).근본의전(根本醫典)"을 중심으로)

  • Chang, Eun-Young;Yun, Chang-Yul
    • Journal of Korean Medical classics
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    • v.11 no.1
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    • pp.416-512
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    • 1998
  • The following conclusions are obtained from the studies on the chapters concerning phisiology, pathology, daily conduct, materia medica, pulse, and urinalysis from , of the "Four Tantras". 1. The theoretical basis forming the Tibetan Medicine is the substance of phlegm, bile, and wind each of which is divided into five kinds. These phisiological substances can be transformed into pathological factors when certain environment is formed. 2. In embryology, the semen of the father and menstral blood of mother is considered the most important condition in conception, and the Five factors are regarded as important. There is a detailed explanation of development of the fetus while it stays in the womb of mother during 38weeks, such as the formation of the viscera, channels, sense organs, etc. 3. There is metaphor which compares the human body with the king's palace. With the development of human anatomy, there is the detailed anatomical picture of anterior and posterior aspects of human body. And also there is the measurement of physiological constitution and the three fluids. 4. In division of the channels, they concerned the now of the blood and distribution of the nerve fibers, and each channel is connected with one another. The division of the cannel is namely embryonic channel, channel of existence, channel of connection, and the course of life principle. 5. The seven bodily constituents and three factors of phlegm, bile, and wind are important in sustaining the life of human body as well as growth and maturization, and when their equilibrium is broken, the human body is degnerated, and finally death comes. 6. The signs of death is divided into distant sign, remote sign, certain sign. and uncertain sign, and is used as a clue in diagnosis of the disease. Especially there is a mention about the mechanism of the dreams, and different dreams according to the condition of the patient. 7. In pathology, there is the cause of the disease, the environmental factors which can induce disease, the path by which disease come into the human body, the characteristics of the disease, and the kinds of disease. 8. There is a mention about the conduct, and it is divided into the daily conduct, the mental attitude, and the side-effects which can occur when one puts up with the physiological actions of the body. 9. The daily diet is divided into food and beverage. The food is divided again into grain, meat, fat, boiled food, and spiced food, and the beverage into milk, water, and wine. 10. The pulsation should be taken in lift hand to diagnose heart, small intestine, stomach, spleen, kidney, reproductive organ, and in right hand jungs, large intestine, liver, gall bladder, kidney, and bladder. In the healthy person, the pulse moves 5times in one perspiration, and the type of pulse is constant while the pulse moves 100times. But unhealthy person's pulse is different from this. The urinalysis is the unique part of Tibetan Medicine, and is important in examination of the disease. One should decide which of the three factors are dominant by the obervation of the color, amount of the steam and how long it lasts, odour, foam, and the shape of the swirl in three different states when the urine is hot, warm, and cold. One can determine the life of the patient and which viscera is the cause of the disease by the pulse, and whether the nature of the disease is hot or cold by the urinalysis. 11. The materia medica contains gemstones, minerals, plateau medication, and meat products.

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The Impact of O4O Selection Attributes on Customer Satisfaction and Loyalty: Focusing on the Case of Fresh Hema in China (O4O 선택속성이 고객만족도 및 고객충성도에 미치는 영향: 중국 허마셴셩 사례를 중심으로)

  • Cui, Chengguo;Yang, Sung-Byung
    • Knowledge Management Research
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    • v.21 no.3
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    • pp.249-269
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    • 2020
  • Recently, as the online market has matured, it is facing many problems to prevent the growth. The most common problem is the homogenization of online products, which fails to increase the number of customers any more. Moreover, although the portion of the online market has increased significantly, it now becomes essential to expand offline for further development. In response, many online firms have recently sought to expand their businesses and marketing channels by securing offline spaces that can complement the limitations of online platforms, on top of their existing advantages of online channels. Based on their competitive advantage in terms of analyzing large volumes of customer data utilizing information technologies (e.g., big data and artificial intelligence), they are reinforcing their offline influence as well through this online for offline (O4O) business model. On the other hand, most of the existing research has primarily focused on online to offline (O2O) business model, and there is still a lack of research on O4O business models, which have been actively attempted in various industrial fields in recent years. Since a few of O4O-related studies have been conducted only in an experience marketing setting following a case study method, it is critical to conduct an empirical study on O4O selection attributes and their impact on customer satisfaction and loyalty. Therefore, focusing on China's representative O4O business model, 'Fresh Hema,' this study attempts to identify some key selection attributes specialized for O4O services from the customers' viewpoint and examine the impact of these attributes on customer satisfaction and loyalty. The results of the structural equation modeling (SEM) with 300 O4O (Fresh Hema) experienced customers, reveal that, out of seven O4O selection attributes, four (mobile app quality, mobile payment, product quality, and store facilities) have an impact on customer satisfaction, which also leads to customer loyalty (reuse intention, recommendation intention, and brand attachment). This study would help managers in an O4O area well adapt to rapidly changing customer needs and provide them with some guidelines for enhancing both customer satisfaction and loyalty by allocating more resources to more significant selection attributes, rather than less significant ones.

A study on The Pulse taking diagnostics of Nan Jing 1-23 Nan (난경(難經) 1-23난중(難中) 맥학조(脈學條)에 관한 연구(硏究))

  • Kim, Bup-Jin;Park, Won-Hwan
    • The Journal of Dong Guk Oriental Medicine
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    • v.8 no.2
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    • pp.131-154
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    • 2000
  • Nan Jing(Difficult Classic), as a catechism, describes in detail and deeply the ideas in Nei Jing(Huangdi's Internal Classic). The description of Nan Jing is focused on basic theories including theories about some disease and is excellent in identification and analysis. The contents of Nan Jing are as follows: 1-23 Nan-pulse and pulse condition, 24~29 Nan-channels and collaterals, 30~47 Nan-viscera and bowels(Zang Fu organs), 48~61 Nan-disease, 62~68 Nan-acupuncture points, 69~91 Nan-acupuncture. Especially, diagnosis techniques in Nan Jing make 'Only method of cunkou pulse taking' that is a technique for feeling the pulse widely applied in these days in Oriental medicine clear. Thus, this book adjusts the theory of pulse and pulse condition given in 1~23 Nan of 'The Study of Nan Jing' in order to enhance an understanding about the theory of pulse and pulse condition. The text of 1~23 Nan about pulse lore centers on all pulse of human body interconnected each other and cunkou, both ends of the pulse, and contrasts regular pulse with irregular pulse. 1. 10 Nan describes the theory about five kinds of evils and hardness and softness, and unique pulse condition of each bowels. 2. 13 Nan explains that the relative difficulty of medical treatment is determined by the degree of balance or unbalance among three factors-colors, pulse and pulse condition, flesh shape. 3. 14 Nan divides pulse and pulse condition into slow pulse and rapid pulse, and explains separately abnormality, great loss of semen, death caused by slow pulse, and abnormality, great loss of semen, death caused by rapid pulse. 4. 15 Nan about taut pulse(弦), full pulse(鉤), floating pulse(毛), deep pulse(石脈) describes that pulse and pulse condition differs according to four seasons. Therefore, Nan Jing establishes clearly techniques of feeling the pulse in 'Only method of cunkou pulse taking(獨取寸口)' and advances the theory of Nei Jing. Futhermore, Nan Jing is more valuable in that it suggests unique theory different with Nei Jing.

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An Exploratory Empirical Study on Shopping Choice in Retail Channels by the Selective Characteristics of Foods (상품 선택 특성에 따른 쇼핑채널 선택에 관한 연구: 식품 MD를 중심으로)

  • Ha, Kwang-Ok;Lee, Jung-Hee
    • The Journal of Small Business Innovation
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    • v.20 no.1
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    • pp.35-46
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    • 2017
  • The purpose of this study is to obtain the implications for establishing a marketing strategy for retailers by analyzing whether the consumer's preference for products (food) is influenced by on-line, off-line, and omni-channel preferences. The research model consisted of the effects of consumers' food selection characteristics on business preference and omni channel preference. The results of analysis based on 477 questionnaires are summarized as follows. First, food purchasing characteristics that utilize the seven characteristics of (1) freshness of food, (2) taste, (3) quality and safety, (4) tasting, (5) food function and information, (6) country of origin, and (7) brand loyalty, has various effects on types of business preference, omni-channel preference. The adopted hypotheses were selected in order of brand loyalty (5 times), freshness (3 times), tasting (3 times), and origin (1 time). The selective attributes on foods are: (1) what kind of brand, (2) how good the freshness is, (3) tasting. (4) The country of origin is to be compressed. Actually consumers seem to utilize only the core selective factors that are appropriate to the characteristics of the distribution channel rather than all of them in the shopping of the food, and there is three characteristics on Convenience Store and only one or two factors in the other types of business. Second, in the analysis of the omni-channel preference analysis, food selection characteristics has been shown to have a limited effect, which is attributed to the fact that the consumer has not yet understood the concept of omni channel. Third, the results of this study suggest that there is a need to reflect the selection characteristics of foods that have diverse influences by business type in the marketing strategies. Because consumers make reasonable consumption to use both on-line and off-line simultaneously, consumers who use Omni Channel focus on quality and safety of food, identify products through tasting, pursue brands that can trust anywhere. Customers who pursue rationality will have a high preference for using Omni Channel. Product choice characteristic has significant effect on omni-channel preference. For a few years, omni-channel strategy of retailers meets with a difficulty. This study make a first attempt to study omni-channel preference changing retailing paradigm.

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The Concentration and Input/Output of Nitrogen and Phosphorus in Paddy Fields (논에서의 질소 및 인의 농도와 유출입)

  • Shin, Dong-Seok;Kwun, Soon-Kuk
    • Korean Journal of Environmental Agriculture
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    • v.9 no.2
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    • pp.133-141
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    • 1990
  • For the purpose of evaluating nutrient loadings into rivers and lakes from agricultural land, especially from paddy fields and also nutrient degradation in drainage channels, the Total Kjeldahl Nitrogen(TKN) and the Total Phosphorus(TP) were investigated in 29.5 ha. paddy fields in Hwa-Sung, Kyong-Ki, Korea, during the period from May 8, 1989 to Sep. 27, 1989. The results of the study can be su㎜arized as follows : 1. Annual inputs into paddy fields were 180 N-kg/ha 46 P-kg/ha. by fertilization, and 15.0 TKN-kg/ha. 10.0 TP-kg/ha. by irrigation, 8.0 TKN-kg/ha. 0.34 TP-kg/ha. by rainfall respectively. The amount of nutrient involved in surface runoff from paddies was 39.0 TKN-kg/ha. 9.2 TP-kg/ha. and in seepage 7.5 TKN-kg/ha. 2.1 TP-kg/ha. respectively 2. In WS1 stream(reach length equals 950m), nutrients decreased 0.31 TKN-mg/L/km, 0.01 TP-mg/L/km and in WS2 stream (reach length equals 750m) which are more meandering and undulating than WS1, the nutrients decreased 0.84 TKN-mg/L/km, 0.11 TP-mg/L/km. From these results, it was concluded that low stream velocity due to meandering and undulation promotes more degradation of nutrient concentrations. 3. For the purpose of decreasing nutrient loads from paddy fields, the amount of fertilizer used needs to be controlled, irrigation weirs need to be constructed in the drainage channels to delay the transportation of nutrients by decelerating the stream velocity and plants such as plantain-lily need to be cultivated in the channel to consume nutrients and therefore enlarge chances of self-purification.

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A Case Study on Forecasting Inbound Calls of Motor Insurance Company Using Interactive Data Mining Technique (대화식 데이터 마이닝 기법을 활용한 자동차 보험사의 인입 콜량 예측 사례)

  • Baek, Woong;Kim, Nam-Gyu
    • Journal of Intelligence and Information Systems
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    • v.16 no.3
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    • pp.99-120
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    • 2010
  • Due to the wide spread of customers' frequent access of non face-to-face services, there have been many attempts to improve customer satisfaction using huge amounts of data accumulated throughnon face-to-face channels. Usually, a call center is regarded to be one of the most representative non-faced channels. Therefore, it is important that a call center has enough agents to offer high level customer satisfaction. However, managing too many agents would increase the operational costs of a call center by increasing labor costs. Therefore, predicting and calculating the appropriate size of human resources of a call center is one of the most critical success factors of call center management. For this reason, most call centers are currently establishing a department of WFM(Work Force Management) to estimate the appropriate number of agents and to direct much effort to predict the volume of inbound calls. In real world applications, inbound call prediction is usually performed based on the intuition and experience of a domain expert. In other words, a domain expert usually predicts the volume of calls by calculating the average call of some periods and adjusting the average according tohis/her subjective estimation. However, this kind of approach has radical limitations in that the result of prediction might be strongly affected by the expert's personal experience and competence. It is often the case that a domain expert may predict inbound calls quite differently from anotherif the two experts have mutually different opinions on selecting influential variables and priorities among the variables. Moreover, it is almost impossible to logically clarify the process of expert's subjective prediction. Currently, to overcome the limitations of subjective call prediction, most call centers are adopting a WFMS(Workforce Management System) package in which expert's best practices are systemized. With WFMS, a user can predict the volume of calls by calculating the average call of each day of the week, excluding some eventful days. However, WFMS costs too much capital during the early stage of system establishment. Moreover, it is hard to reflect new information ontothe system when some factors affecting the amount of calls have been changed. In this paper, we attempt to devise a new model for predicting inbound calls that is not only based on theoretical background but also easily applicable to real world applications. Our model was mainly developed by the interactive decision tree technique, one of the most popular techniques in data mining. Therefore, we expect that our model can predict inbound calls automatically based on historical data, and it can utilize expert's domain knowledge during the process of tree construction. To analyze the accuracy of our model, we performed intensive experiments on a real case of one of the largest car insurance companies in Korea. In the case study, the prediction accuracy of the devised two models and traditional WFMS are analyzed with respect to the various error rates allowable. The experiments reveal that our data mining-based two models outperform WFMS in terms of predicting the amount of accident calls and fault calls in most experimental situations examined.

Channel Innovation through Online Transaction processing System in Floral Wholesale Distribution: FLOMARKET Case (화훼도매 온라인 거래처리 시스템을 통한 유통경로 개선방안 연구: (주)플로마켓 사례)

  • Lee, Seungchang;Ahn, Sunghyuck
    • Journal of Distribution Science
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    • v.8 no.1
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    • pp.21-33
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    • 2010
  • The ICT(information & communication technology) led to a dramatic change of floral distribution service, a phase of competition between wholesales and retail stores, and distribution channels in floral industry. It was expected that a role of the intermediaries in this industry would have reduced due to the improvement of transaction process by ICT. However, the ICT made to overcome a regional limit of the floral retail distribution service leading to an increase in sales and enlargement of the stores. And even it made possible to bring out another type of intermediaries such as private associations. This case study focuses on what kinds of efforts the floral wholesale distributors have made to enable a distribution process more smoothly between the wholesale distributors and retail stores through the information system, and what the failure factors in adopting the information system have been. This paper is also to examine how the wholesale distributors have changed themselves to gain dominant positions in distribution channels. As a result of the study, it was found that the intermediaries mostly failed in successfully achieving the distribution channel innovation through the information system because of several main reasons. FLOMARKET Inc. tried to innovate a distribution channel to obtain high quality goods through consolidating a wholesale distribution market in that segregated both floral joint market from free markets. after implementing the information system with consideration of the failure factors, FLOMARKET Inc. was able to minimize goods in stock and make a major purchase of various goods. In addition, it made a possible pre-ordering process and an exact calculation of purchasing goods so they could provide their products with market price in real time, which helped for the company to gain credits from their customers. Also, FLOMARKET Inc. established the information system which well suited to its business stage in order to deal with a rapidly changing distribution environment. It's so obvious that the transaction processing system of FLOMARKET Inc. definitely helped to share information among traders more seamlessly and smoothly in realtime, standardize goods, and make a transaction process clearer. Besides, the transaction information helped the wholesale distributors and retail stores to make more strategic decisions in their business because through the system they enabled to gather the marketing intelligence information more easily and convenient. If we understand that the floral distribution market is characterized by the low IT- based industry, it's worth to examine a case study proving that the information system actually increases the productivity of the transaction process in the floral industry.

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