• Radiation Oncology Journal
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• v.20 no.1
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• pp.41-52
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• 2002

Purpose : 3D conformal radiotherapy, the optimum dose delivered to the tumor and provided the risk of normal tissue unless marginal miss, was restricted by organ motion. For tumors in the thorax and abdomen, the planning target volume (PTV) is decided including the margin for movement of tumor volumes during treatment due to patients breathing. We designed the respiratory gating radiotherapy device (RGRD) for using during CT simulation, dose planning and beam delivery at identical breathing period conditions. Using RGRD, reducing the treatment margin for organ (thorax or abdomen) motion due to breathing and improve dose distribution for 3D conformal radiotherapy. Materials and Methods : The internal organ motion data for lung cancer patients were obtained by examining the diaphragm in the supine position to find the position dependency. We made a respiratory gating radiotherapy device (RGRD) that is composed of a strip band, drug sensor, micro switch, and a connected on-off switch in a LINAC control box. During same breathing period by RGRD, spiral CT scan, virtual simulation, and 3D dose planing for lung cancer patients were peformed, without an extended PTV margin for free breathing, and then the dose was delivered at the same positions. We calculated effective volumes and normal tissue complication probabilities (NTCP) using dose volume histograms for normal lung, and analyzed changes in doses associated with selected NTCP levels and tumor control probabilities (TCP) at these new dose levels. The effects of 3D conformal radiotherapy by RGRD were evaluated with DVH (Dose Volume Histogram), TCP, NTCP and dose statistics. Results : The average movement of a diaphragm was 1.5 cm in the supine position when patients breathed freely. Depending on the location of the tumor, the magnitude of the PTV margin needs to be extended from 1 cm to 3 cm, which can greatly increase normal tissue irradiation, and hence, results in increase of the normal tissue complications probabiliy. Simple and precise RGRD is very easy to setup on patients and is sensitive to length variation (+2 mm), it also delivers on-off information to patients and the LINAC machine. We evaluated the treatment plans of patients who had received conformal partial organ lung irradiation for the treatment of thorax malignancies. Using RGRD, the PTV margin by free breathing can be reduced about 2 cm for moving organs by breathing. TCP values are almost the same values $(4\~5\%\;increased)$ for lung cancer regardless of increasing the PTV margin to 2.0 cm but NTCP values are rapidly increased $(50\~70\%\;increased)$ for upon extending PTV margins by 2.0 cm. Conclusion : Internal organ motion due to breathing can be reduced effectively using our simple RGRD. This method can be used in clinical treatments to reduce organ motion induced margin, thereby reducing normal tissue irradiation. Using treatment planning software, the dose to normal tissues was analyzed by comparing dose statistics with and without RGRD. Potential benefits of radiotherapy derived from reduction or elimination of planning target volume (PTV) margins associated with patient breathing through the evaluation of the lung cancer patients treated with 3D conformal radiotherapy.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.97-103
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• 2010

Purpose: Treating same region with different modalities there is a limit to evaluate the total absorbed dose of normal tissues. The reason is that it does not support to communication each modalities yet. In this article, it evaluates absorbed dose of the patients who had been treated same region by a tomotherapy and a linear accelerator. Materials and Methods: After reconstructing anatomic structure with a anthropomorphic phantom, administrate 45 Gy to a tumor in linac plan system as well as prescribe 15 Gy in tomotherapy plan system for make an ideal treatment plan. After the plan which made by tomoplan system transfers to the oncentra plan system for reproduce plan under the same condition and realize total treatment plan with summation 45 Gy linac treatment plan. To evaluate the absorbed dose of two different modalities, do a comparative study both a simple summation dose values and integration dose values. Then compare and analyze absorbed dose of normal tissues and a tumor with the patients who had been exposured radiation by above two differents modalities. Results: The result of compared data, in case of minimum dose, there are big different dose values in spleen (12.4%). On the other hand, in case of the maximum dose, it reports big different in a small bowel (10.2%) and a cord (5.8%) in head & neck cancer patients, there presents that oral (20.3%), right lens (7.7%) in minimum dose value. About maximum dose, it represents that spinal (22.5), brain stem (12%), optic chiasm (8.9%), Rt lens (11.5%), mandible (8.1%), pituitary gland (6.2%). In case of Rt abdominal cancer patients, there represents big different minimum dose as Lt kidney (20.3%), stomach (8.1%) about pelvic cancer patients, it reports there are big different in minimum dose as a bladder (15.2%) as well as big different value in maximum dose as a small bowel (5.6%), a bladder (5.5%) in addition, making treatment plan it is able us to get. Conclusion: In case of comparing both simple summation absorbed dose and integration absorbed dose, the minimum dose are represented higher as well as the maximum dose come out lower and the average dose are revealed similar with our expected values data. It is able to evaluate tumor & normal tissue absorbed dose which could had been not realized by treatment plan system. The DVH of interesting region are prescribed lower dose than expected. From now on, it needs to develop the new modality which are able to realize exact dose distribution as well as integration absorbed dose evaluation in same treatment region with different modalities.

• Journal of Korean Society of Forest Science
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• v.80 no.1
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• pp.54-71
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• 1991

To classify and analyze the forest communities and their structures, the vegetation in Mt. Joghe was investigated from July, 1980 to August, 1989. The results obtained are as follow ; 1. A total of 750 kinds of vascular plant(49 orders, 122 families, 434 genera, 627 species, 1 subspecies, 111 varieties and 11 forma)were observed in Mt. Ioghe. The newly observed plant species were Dioscorea quingueloba, Spiranthes sinensis, Cephalanthera falcata, Angelica gigas, Clematis patents, Paeonia obovata, Hibiscus mulabilis, Ainsliaea acerifolia, Dictamnus dasycarpus, Cynachum ascyrifolia, Vaccinium koreanum, Erythrortium japonicum, Indigofera kirilowii (17species), Broussonetia kazinoki var, humillis, Euonymus, fortunei var. radicans, Juniperus communis var, nippnnica, Callicarpa japonica var. radicans, Joniperus communis var. rzipponica, Callicarpa japonica var. taquetii (4 varieties) and L indera obtusiloba for. billosum (1 forma). 2. The life spectrum of flora in Mt. Joghe was classified into $CH-D_1-R_5-e$ type. Distribution area was identical to Southern type by Nakai, Lee, and Yim. A few subtropical species were also observed. 3. Simpson's species diversity index(Ds) was 0.9 and Shannon-Weiner's diversity index (H') was 1.004. These indice suggest that the vegetation in Mt. Joghe is of complicated forest communities. 4. Pte-Q was 1.81 which was higher than the nationwide mean of 1.68. Urbanization Index (UI) was 28.75 for naturalized plant species, and 17.49 for exotic woody plant species, which were similar to those of Mt. Baekun and Mt. Naejang. 5. The forest vegetation of Mt. Joghe was grouped in 3 vegetation types : 7 natural plant Communities dominated by Quercus serrat, Quercus acutissima, Quercus variabilis, Carpinus laxiflora, Pinus derasiflora and Platycarya strobilacea, 8 substitutional plant communities Styrax japonica, Stewartia koreana, Lindera erytlrrocarpa, Zelkova serrata, Rhtrs chinensis, Controversa, and Frzrxirtus manrlshurica, and 7 plantation Communities composed of Pinus koraiensis, Pinus rigida, Magnolia nbnvata, Chamecyparis obkrsa, Larie ieptolepis, Castanea crenata and Cryptomeria japonica. 6. Actual vegetation maps and profile diagrams were made by phytosocialogical classification. 7. As the important and unique species in Mt. Joghe, Lindera sericea, Penicaria tilitorme, Hex macropoda, Hex macropoda for. pseudo-macropoda, Steroartia koreana, Adenopkora palustris and Corylop.,is coreana, which were also seported by Lee(1977), Kim and Yark(1989), were identified and Vaccinium coreanum, Cremastra appendiculinium, Juniperus comminis van. nipponica, Cephalanthera falcata, Broussortetia kazinoki var. humilis, paeonia obovata, Deutzia prunifolia, Dictamnus dasyarpus, Angelica gigics and Bupleurum falcatum were odditionally observed.

• Journal of Global Scholars of Marketing Science
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• v.17 no.4
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• pp.247-269
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• 2007

In recent years, one of the major reasons for the fierce competition amongst firms is that they strive to increase their own market shares and customer acquisition rate in the same market with similar and apparently undifferentiated products in terms of quality and perceived benefit. Because of this change in recent marketing environment, the differentiated after-sales service and diversified promotion strategies have become more important to gain competitive advantage. Price promotion is the favorite strategy that most retailers use to achieve short-term sales increase, induce consumer's brand switch, in troduce new product into market, and so forth. However, if marketers apply or copy an identical price promotion strategy without considering the characteristic differences in product and consumer preference, it will cause serious problems because discounted price itself could make people skeptical about product quality, and the changes of perceived value might appear differently depending on other factors such as consumer involvement or brand attitude. Previous studies showed that price promotion would certainly increase sales, and the discounted price compared to regular price would enhance the consumer's perceived values. On the other hand, discounted price itself could make people depreciate or skeptical about product quality, and reduce the consumers' positivity bias because consumers might be unsure whether the current price promotion is the retailer's best price offer. Moreover, we cannot say that discounted price absolutely enhances the consumer's perceived values regardless of product category and purchase situations. That is, the factors that affect consumers' value perceptions and buying behavior are so diverse in reality that the results of studies on the same dependent variable come out differently depending on what variable was used or how experiment conditions were designed. Majority of previous researches on the effect of price-comparison advertising have used consumers' buying behavior as dependent variable. In order to figure out consumers' buying behavior theoretically, analysis of value perceptions which influence buying intentions is needed. In addition, they did not combined the independent variables such as brand loyalty and price discount rate together. For this reason, this paper tried to examine the moderating effect of brand loyalty on relationship between the different levels of discounting rate and buyers' value perception. And we provided with theoretical and managerial implications that marketers need to consider such variables as product attributes, brand loyalty, and consumer involvement at the same time, and then establish a differentiated pricing strategy case by case in order to enhance consumer's perceived values properl. Three research concepts were used in our study and each concept based on past researches was defined. The perceived acquisition value in this study was defined as the perceived net gains associated with the products or services acquired. That is, the perceived acquisition value of the product will be positively influenced by the benefits buyers believe they are getting by acquiring and using the product, and negatively influenced by the money given up to acquire the product. And the perceived transaction value was defined as the perception of psychological satisfaction or pleasure obtained from taking advantage of the financial terms of the price deal. Lastly, the brand loyalty was defined as favorable attitude towards a purchased product. Thus, a consumer loyal to a brand has an emotional attachment to the brand or firm. Repeat purchasers continue to buy the same brand even though they do not have an emotional attachment to it. We assumed that if the degree of brand loyalty is high, the perceived acquisition value and the perceived transaction value will increase when higher discount rate is provided. But we found that there are no significant differences in values between two different discount rates as a result of empirical analysis. It means that price reduction did not affect consumer's brand choice significantly because the perceived sacrifice decreased only a little, and customers are satisfied with product's benefits when brand loyalty is high. From the result, we confirmed that consumers with high degree of brand loyalty to a specific product are less sensitive to price change. Thus, using price promotion strategy to merely expect sale increase is not recommendable. Instead of discounting price, marketers need to strengthen consumers' brand loyalty and maintain the skimming strategy. On the contrary, when the degree of brand loyalty is low, the perceived acquisition value and the perceived transaction value decreased significantly when higher discount rate is provided. Generally brands that are considered inferior might be able to draw attention away from the quality of the product by making consumers focus more on the sacrifice component of price. But considering the fact that consumers with low degree of brand loyalty are known to be unsatisfied with product's benefits and have relatively negative brand attitude, bigger price reduction offered in experiment condition of this paper made consumers depreciate product's quality and benefit more and more, and consumer's psychological perceived sacrifice increased while perceived values decreased accordingly. We infer that, in the case of inferior brand, a drastic price-cut or frequent price promotion may increase consumers' uncertainty about overall components of product. Therefore, it appears that reinforcing the augmented product such as after-sale service, delivery and giving credit which is one of the levels consisting of product would be more effective in reality. This will be better rather than competing with product that holds high brand loyalty by reducing sale price. Although this study tried to examine the moderating effect of brand loyalty on relationship between the different levels of discounting rate and buyers' value perception, there are several limitations. This study was conducted in controlled conditions where the high involvement product and two different levels of discount rate were applied. Given the presence of low involvement product, when both pieces of information are available, it is likely that the results we have reported here may have been different. Thus, this research results explain only the specific situation. Second, the sample selected in this study was university students in their twenties, so we cannot say that the results are firmly effective to all generations. Future research that manipulates the level of discount along with the consumer involvement might lead to a more robust understanding of the effects various discount rate. And, we used a cellular phone as a product stimulus, so it would be very interesting to analyze the result when the product stimulus is an intangible product such as service. It could be also valuable to analyze whether the change of perceived value affects consumers' final buying behavior positively or negatively.