• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.134-135
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• 2011

양자점은 전자와 양공을 3차원으로 속박 시키므로 기존의 bulk나 양자우물보다 양자점을 이용한 레이저 다이오드의 경우 낮은 문턱 전류, 높은 미분이득 및 온도 안전성의 장점이 있을 거라 기대되고 있다. 그러나, 양자점은 낮은 areal coverage 때문에 높은 속박효율을 얻지 못하고 있다. 이러한 양자점의 문제점을 해결하기 위해 양자점을 양자우물 안에 성장시켜 운반자들의 포획을 향상시키는 방법들이 연구되고 있다. 양자우물 안에 양자점을 넣으면 양자우물이 운반자들의 포획을 증가 시키고, 열적 방출도 억제하여 온도 안정성이 향상 되는 것으로 알려져 있다. 광통신 대역의 1.3 ${\mu}m$ 경우, GaAs계를 이용하여 InAs 양자점을 strained InGaAs 박막을 우물층으로 한 dot-in-a-well 구조의 연구는 몇몇 보고된 바 있다. 그러나 InP계를 사용하는 1.55 ${\mu}m$ 대역에서 dot-in-a-well구조의 연구는 아직 미미하다. 본 연구에서는 유기 금속 화학 증착법(metal organic chemical vapor deposition)을 이용하여 InP 기판 위에 InAs 양자점을 자발성장법으로 성장하였으며 dot-in-a-well 구조에서 우물층으로 1.35 ${\mu}m$ 파장의 $In_{0.69}Ga_{0.31}As_{0.67}P_{0.33}$ (1.35Q)를, 장벽층으로는 1.1 ${\mu}m$ 파장의 $In_{0.85}Ga_{0.15}As_{0.32}P_{0.68}$(1.1Q)를 사용하였다. 양자우물층과 장벽층은 모두 InP 기판과 격자가 일치하는 조건으로 성장하였다. III족 원료로는 trimethylindium (TMI)와 trimethylgalium (TMGa)을 사용하였으며 V족 원료 가스로는 $PH_3$ 100%, $AsH_3$ 100%를, carrier gas로는 $H_2$를 사용하였다. InP buffer층의 성장 온도는 640$^{\circ}C$이며 양자점 성장 온도는 520$^{\circ}C$이다. 양자점 형성은 원자력간 현미경(Atomic force microscopy)를 이용하여 확인하였으며, 박막의 결정성은 쌍결정 회절분석(Double crystal x-ray deffractometry)를 이용하여 확인하였다. 확인된 성장 조건을 이용하여 양자점 시료를 성장하였으며 광여기분광법(Photoluminescence)을 이용하여 광특성을 분석하였다. Fig. 1은 dot in a barrier 와 dot-in-a-well 시료의 성장구조이다. Fig. 1(a)는 일반적인 dot-in-a-barrier 구조로 InP buffer층을 성장하고 1.1Q를 100 nm 성장한 후 양자점을 성장하였다. 그 후 1.1Q 100 nm와 InP 100 nm로 capping하였다. Fig. 1(b)는 dot-in-a-well 구조로 InP buffer층을 성장하고 1.1Q를 100 nm 성장 후 1.35Q 우물층을 4 nm 성장하였다. 그 위에 InAs 양자점을 성장하였다. 그 후에 1.35Q 우물층을 4 nm 성장하고 1.1Q 100 nm와 InP 100 nm로 capping하였다. Fig. 2는 dot-in-a-barrier 시료와 dot-in-a-well 시료의 상온 PL data이다. Dot-in-a-barrier 시료의 PL 파장은 1544 nm이며 반치폭은 79.70 meV이다. Dot-in-a-well 시료의 파장은 1546 nm이며 반치폭은 70.80 meV이다. 두 시료의 PL 파장 변화는 없으며, 반치폭은 dot-in-a-well 시료가 8.9 meV 감소하였다. Dot-in-a-well 시료의 PL peak 강도는 57% 증가하였으며 적분강도(integration intensity)는 45%가 증가하였다. PL 데이터에서 높은 에너지의 반치폭 변화는 없으며 낮은 에너지의 반치폭은 8 meV 감소하였다. 적분강도 증가에서 dot-in-a-well 구조가 dot-in-a-barrier 구조보다 전자-양공의 재결합이 증가한다는 것을 알 수 있으며, 반치폭 변화로부터 특히 높은 에너지를 갖는 작은 양자점에서의 재결합이 증가 된 것을 알 수 있다. 이는 양자우물이 장벽보다 전자-양공의 구속력을 증가시키기 때문에 양자점에 전자와 양공의 공급을 증가시키기 때문이다. 따라서 낮은 에너지를 가지는 양자점을 모두 채우고 높은 에너지를 가지는 양자점까지 채우게 되므로, 높은 에너지를 가지는 양자점에서의 전자-양공 재결합이 증가되었기 때문이다. 뿐만 아니라 파장 변화 없이 PL peak 강도와 적분강도가 증가하고 낮은 에너지 쪽의 반치폭이 감소한 것으로부터 에너지가 낮은 양자점보다는 에너지가 높은 양자점에서의 전자-양공 재결합율이 급증하였음을 알 수 있다. 우리는 이와 같은 연구에서 InP계를 이용해 1.55 ${\mu}m$에서도 dot in a well구조를 성장 하여 더 좋은 특성을 낼 수 있으며 앞으로 많은 연구가 필요할 것이라 생각한다.

• Journal of Dairy Science and Biotechnology
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• v.33 no.2
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• pp.111-118
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• 2015

Probiotic, prebiotic, and synbiotic substances as well as microorganisms were added to infant formula in an attempt to influence the intestinal microflora with an aim to stimulate the growth of lactic acid bacteria, especially bifidobacteria and lactobacilli. Over the last 10 years, new synbiotic infant formulas containing probiotics and prebiotics have been proposed in order to simulate the effect of breast-feeding on the intestinal microflora. Owing to their synergistic effect, the new synbiotics are expected to be more helpful than using probiotics and prebiotics individually. Maintenance of the viability of the probiotics during food processing and the passage through the gastrointestinal tract should be the most important consideration, since a sufficient number of bacteria ($10^8cfu/g$) should reach the intended location to have a positive effect on the host. Storage conditions and the processing technology used for the manufacture of products such as infant formula adversely affect the viability of the probiotics. When an appropriate and cost-effective microencapsulation methodology using the generally recognized as safe (GRAS) status and substances with high biological value are developed, the quality of infant formulas would improve. The effect of probiotics may be called a double-effect, where one is an immunomodulatory effect, induced by live probiotics that advantageously alter the gastrointestinal microflora, and the other comprises anti-inflammatory responses elicited by dead cells. At present, a new terminology is required to define the dead microorganisms or crude microbial fractions that positively affect health. The term "paraprobiotics" (or ghost probiotics) has been proposed to define dead microbial cells (not damaged or broken) or crude cell extracts (i.e., cell extracts with complex chemical composition) that are beneficial to humans and animals when a sufficient amount is orally or topically administered. The fecal microflora of bottle-fed infants is altered when the milk-based infant formula is supplemented with probiotics or prebiotics. Thus, by increasing the proportion of beneficial bacteria such as bifidobacteria and lactobacilli, prebiotics modify the fecal microbial composition and accordingly regulate the activity of the immune system. Therefore, considerable attention has been focused on the improvement of infant formula quality such that its beneficial effects are comparable to those of human milk, using prebiotics such as inulin and oligosaccharides and potential specific probiotics such as bifidobacteria, which selectively stimulate the proliferation of beneficial bacteria in the microflora and the indigenous intestinal metabolic activity of the microflora.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.743-752
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• 2004

This experiment was conducted to investigate the effect of filtered water with silicate minerals on growth performance and pork quality. A total of 64 pigs were allotted at 37.95 kg body weight to 4 treatments in a randomized complete block(RCB) design. Each treatment had 4 replicates and treatments were I) Con(basaI diet). 2) Si-I(consumed silicate mineral filtered water and silicate mineral additive during 4 weeks before market weight), 3) Si-Il( consumed silicate mineral filtered water and silicate mineral additive during 8 weeks before market weight) and 4) Si-I1I(consumed silicate mineral filtered water and silicate mineral additive during 12 weeks before market weight). Silicate complex was added at 0.8% to basal diet. All pigs were allowed to feed and water ad libitum for 12 weeks. During last 4 weeks, average daily gain(ADG) in Si-Il and Si-III group was higher than that in Si-I group(P < 0.05). However overall experimental period, there were no significant differences in growth performance among all treatments. Acceptability of cooked pork at 7th day after slaughter in Si-lII group was higher than that in Con group(P < 0.05). The value of pH of fresh pork at 6 hours after slaughter was lower in Si-I1I group than that in Con group(P < 0.05). TBA values of fresh pork at 14th day after slaughter were lower in Si-II and Si-III groups than Con group(P < 0.05). These results demonstrated that pork quality could be improved when pigs consumed both silicate mineral and silicate mineral filtered water. However, growth performance was not improved by the consumption of silicate mineral filtered water and silicate mineral.

• Journal of KIISE:Databases
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• v.33 no.6
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• pp.600-619
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• 2006

According to recent technical advances on sensors and mobile devices, processing of data streams generated by the devices is becoming an important research issue. The data stream of real values obtained at continuous time points is called streaming time-series. Due to the unique features of streaming time-series that are different from those of traditional time-series, similarity matching problem on the streaming time-series should be solved in a new way. In this paper, we propose an efficient algorithm for streaming time- series matching problem that supports normalization transform. While the existing algorithms compare streaming time-series without any transform, the algorithm proposed in the paper compares them after they are normalization-transformed. The normalization transform is useful for finding time-series that have similar fluctuation trends even though they consist of distant element values. The major contributions of this paper are as follows. (1) By using a theorem presented in the context of subsequence matching that supports normalization transform[4], we propose a simple algorithm for solving the problem. (2) For improving search performance, we extend the simple algorithm to use $k\;({\geq}\;1)$ indexes. (3) For a given k, for achieving optimal search performance of the extended algorithm, we present an approximation method for choosing k window sizes to construct k indexes. (4) Based on the notion of continuity[8] on streaming time-series, we further extend our algorithm so that it can simultaneously obtain the search results for $m\;({\geq}\;1)$ time points from present $t_0$ to a time point $(t_0+m-1)$ in the near future by retrieving the index only once. (5) Through a series of experiments, we compare search performances of the algorithms proposed in this paper, and show their performance trends according to k and m values. To the best of our knowledge, since there has been no algorithm that solves the same problem presented in this paper, we compare search performances of our algorithms with the sequential scan algorithm. The experiment result showed that our algorithms outperformed the sequential scan algorithm by up to 13.2 times. The performances of our algorithms should be more improved, as k is increased.

• Phonetics and Speech Sciences
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• v.11 no.3
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• pp.69-76
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• 2019

This study aimed to investigate the effects of vocal aerobic treatment (VAT) on the improvement of voice in patients with voice disorders. Twenty patients (13 males, 7 females) were diagnosed with voice disorders on the basis of videostroboscopy and voice evaluations. Acoustic evaluation was performed with the Multidimensional voice program (MDVP) and Voice Range Profile (VRP) of Computerized Speech Lab (CSL), and aerodynamic evaluation with PAS (Phonatory Aerodynamic System). The changes in F0, Jitter, Shimmer, and NHR before and after treatment were measured by MDVP. F0 range and Energy range were measured with VRP before and after treatment, and the changes in Expiratory Volume (FVC), Phonation Time (PHOT), Mean Expiratory Airflow (MEAF), Mean Peak Air Pressure (MPAP), and Aerodynamic Efficiency (AEFF) with PAS. Videostroboscopy was performed to evaluate the regularity, symmetry, mucosal wave, and amplitude changes of both vocal cords before and after treatment. Voice therapy was performed once a week for each patient using the VAT program in a holistic voice therapy approach. The average number of treatments per patient was 6.5. In the MDVP, Jitter, Shimmer, and NHR showed statistically significant decreases (p < .001, p < .01, p < .05). VRP results showed that Hz and semitones in the frequency range improved significantly after treatment (p < .01, p < .05), as did PAS, FVC, and PHOT (p < .01, p < .001). The results for videostroboscopy, functional voice disorder, laryngopharyngeal reflux, and benign vocal fold lesions were normal. Thus, the VAT program was found to be effective in improving the acoustic and aerodynamic aspects of the voice of patients with voice disorders. In future studies, the effect of VAT on the same group of voice disorders should be studied. It is also necessary to investigate subjective voice improvement and objective voice improvement. Furthermore, it is necessary to examine the effects of VAT in professional voice users.

• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.7-7
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• 2023

Currently, the main technologies of various fourth industries are big data, the Internet of Things, artificial intelligence, blockchain, mixed reality (MR), and drones. In particular, "digital twin," which has recently become a global technological trend, is a concept of a virtual model that is expressed equally in physical objects and computers. By creating and simulating a Digital twin of software-virtualized assets instead of real physical assets, accurate information about the characteristics of real farming (current state, agricultural productivity, agricultural work scenarios, etc.) can be obtained. This study aims to streamline agricultural work through automatic water management, remote growth forecasting, drone control, and pest forecasting through the operation of an integrated control system by constructing digital twin data on the main production area of the nojinot industry and designing and building a smart farm complex. In addition, it aims to distribute digital environmental control agriculture in Korea that can reduce labor and improve crop productivity by minimizing environmental load through the use of appropriate amounts of fertilizers and pesticides through big data analysis. These open-field agricultural technologies can reduce labor through digital farming and cultivation management, optimize water use and prevent soil pollution in preparation for climate change, and quantitative growth management of open-field crops by securing digital data for the national cultivation environment. It is also a way to directly implement carbon-neutral RED++ activities by improving agricultural productivity. The analysis and prediction of growth status through the acquisition of the acquired high-precision and high-definition image-based crop growth data are very effective in digital farming work management. The Southern Crop Department of the National Institute of Food Science conducted research and development on various types of open-field agricultural smart farms such as underground point and underground drainage. In particular, from this year, commercialization is underway in earnest through the establishment of smart farm facilities and technology distribution for agricultural technology complexes across the country. In this study, we would like to describe the case of establishing the agricultural field that combines digital twin technology and open-field agricultural smart farm technology and future utilization plans.

• Management & Information Systems Review
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• v.38 no.1
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• pp.23-41
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• 2019

Smart Factory is different from existing factory automation in that it aims to produce personalized products with minimum time and cost through ICT. However, previous researches, not from consumers but from product suppliers, have focused on technology trends and technology application methods. In order for Smart Factory to be successful, it must go beyond supplier-focus to meet the needs of consumers. In this study, we surveyed the purchase intention of the personalized product manufactured by smart factory. Influencing factors of purchase intention were drawn as consumers' need for uniqueness, innovativeness, need for touch, and privacy concern, based on previous research. As results of data analysis, it was confirmed that respondents were willing to purchase personalized products, and that consumers' need for uniqueness, innovativeness, and need for touch had a significant impact on purchase intention of personalized products. Our findings can be summarized as follows. First, Consumers' need for uniqueness was found to have positive effects(${\beta}=0.168$) on purchase intention of personalized products. The desire to differentiate themselves from others will be reflected in their personalized products. Therefore, consumers with a higher desire for uniqueness tend to be more willing to purchase personalized products. Second, consumer innovativeness was found to have positive effects(${\beta}=0.233$) on purchase intention of personalized products. Personalized shoes suggested in this study is a new type of personalized product that is manufactured by the latest information and communication technologies such as multi-function robots and 3D printing. Therefore, consumers seeking innovative new experiences are more willing to purchase personalized products. Third, need for touch was found to have positive effects(${\beta}=0.299$) on purchase intention of personalized products. In a smart factory environment, prosuming participation is given to consumers. If consumers participate in the product development process and reflect their requirements on the product, they are expected to increase their purchase intention by virtually satisfying the need for touch. Fourth, privacy concern was found to have no significantly related to purchase intention of personalized products. This is interpreted as a willingness to tolerate the risk of exposing personal information such as home address, telephone number, body size, and preference for consumers who feel highly useful in personalized products.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.383-391
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• 2007

This study was conducted for an assessment through the estimation of soil loss by each catchment classified by soil catena. Ten catchments, which are Geumgang21, Namgang03, Dongjincheon, Gapyongcheon01, Gyongancheon02, Geumgang16, Byongsungcheon01, Daesincheon, Bukcheon02, Youngsangang08, were selected from the hydrologic unit map and the detailed soil digital map (1:25,000) for this study. The catchments like Geumgang21, Namgang03, Dongjincheon, Gapyongcheon01 and Gyongancheon02 were mainly composed with soils originated from gneiss. The catchments like Geumgang16, Byongsungcheon01, Daesincheon, Bukcheon02 and Youngsangang08 were mainly composed with soils originated from granites. The grades, which are divided into seven grades with A(very tolerable), B(tolerable), C(moderate), D(low), E(high), F(severe), G(very severe), of soil erosion estimated by USLE in catchments were distributed in most A and B because of paddy land and forestry. In detailed, the soil erosion grade of catchments mainly distributing soils originated from gneiss showed more the distribution of B and C than it of catchments mainly distributing soils originated from granites. The reason of results would be derived from topographic characteristics of soils originated from gneiss located at mountainous. The soil loss according to soil catena linked with Songsan and Jigok series, which are soils originated from gneiss was calculated with $7.66ton\;ha^{-1}\;yr^{-1}$. The soil loss of Geumgang16, Byongsungcheon01, Daesincheon, Bukcheon02 which have the soil catena linked with Samgak and Sangju soil series originated from granite, was calculated with $5.55ton\;ha^{-1}\;yr^{-1}$. The soil loss of Youngsangang08 which have the soil catena linked with Songjung and Baeksan soil series originated from granite was calculated with $9.6ton\;ha^{-1}\;yr^{-1}$, but the conclusion on soil loss in this kind of soil catena would be drawn from the analysis of more catchments. In conclusion, the results of this study inform that the classification of soil catena by catchments and estimation of soil loss according to soil catena would be effective for analysis on the grade of non-point pollution by soil erosion in a catchment.

• Journal of Animal Science and Technology
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• v.44 no.3
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• pp.305-314
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• 2002

For the Exp. 1, a total of seventy two pigs (10.53${\pm}$0.02kg average initial body weight) were used in a 38-d growth assay to determine the effects of Saccharomyces cerevisiae (SC) supplementation on growth performance and fecal microbial populations. Dietary treatments included 1) CON (corn-dried whey-SBM based diet), 2) SC0.2 (CON diet+0.2% SC) and 3) SC0.4 (CON diet+0.4% SC). Through the entire experimental period, ADG, ADFI and gain/feed were not significantly different among the treatments. At d 7 and 14 after the onset of the experiment, fecal Lactobacilli sp. count increased as the concentration of SC in the diets was increased (linear effect, P$<$0.01). At d 7 after the onset of the experiment, fecal Escherichia coli count decreased as the concentration of SC in the diets was increased (linear effect, P$<$0.02, quadratic effect, P$<$0.03). For the Exp. 2, forty five pigs (49.71${\pm}$0.45kg average initial body weight) were used in a 28-d growth assay to determine the effects of complex probiotics (CPB, Phichia anomala ST, Galactomyces geotrichum SR59, Thiobacillus sp.) supplementation on growth performance, nutrient digestibility and fecal $NH_3$-N and volatile fatty acid concentrations. Dietary treatments included 1) CON (corn-SBM based diet), 2) CPB0.2 (CON diet+0.2% CPB) and 3) CPB0.3 (CON diet+0.3% CPB). Through the entire experimental period, pigs fed CPB0.3 diet significantly increased their ADG compared to pigs fed CON and CPB0.2 diets (P$<$0.05). Also, apparent digestibility of DM and N in pigs fed CPB0.3 diet was greater than for pigs fed CON diet (P$<$0.05). Fecal $NH_3$-N decreased (P$<$0.05) in the pigs fed CPB diet compared to pigs fed CON diets. Also, pigs fed CPB0.3 diet significantly decreased their fecal propionic acid compared to pigs fed CON diets (P$<$0.05). In conclusion, the results obtained from these feeding trials suggest that the dietary SC for nursery pigs affects fecal microbial population. In finishing pigs, supplemental CPB was effective to improve ADG and nutrient digestibility but to decrease fecal noxious gas emission.

• Journal of Intelligence and Information Systems
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• v.18 no.4
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• pp.43-57
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• 2012

To enhance the competitive advantage in a constantly changing business environment, an enterprise management must make the right decision in many business activities based on both internal and external information. Thus, providing accurate information plays a prominent role in management's decision making. Intuitively, historical data can provide a feasible estimate through the forecasting models. Therefore, if the service department can estimate the service quantity for the next period, the service department can then effectively control the inventory of service related resources such as human, parts, and other facilities. In addition, the production department can make load map for improving its product quality. Therefore, obtaining an accurate service forecast most likely appears to be critical to manufacturing companies. Numerous investigations addressing this problem have generally employed statistical methods, such as regression or autoregressive and moving average simulation. However, these methods are only efficient for data with are seasonal or cyclical. If the data are influenced by the special characteristics of product, they are not feasible. In our research, we propose a forecasting framework that predicts service demand of manufacturing organization by combining Case-based reasoning (CBR) and leveraging an unsupervised artificial neural network based clustering analysis (i.e., Self-Organizing Maps; SOM). We believe that this is one of the first attempts at applying unsupervised artificial neural network-based machine-learning techniques in the service forecasting domain. Our proposed approach has several appealing features : (1) We applied CBR and SOM in a new forecasting domain such as service demand forecasting. (2) We proposed our combined approach between CBR and SOM in order to overcome limitations of traditional statistical forecasting methods and We have developed a service forecasting tool based on the proposed approach using an unsupervised artificial neural network and Case-based reasoning. In this research, we conducted an empirical study on a real digital TV manufacturer (i.e., Company A). In addition, we have empirically evaluated the proposed approach and tool using real sales and service related data from digital TV manufacturer. In our empirical experiments, we intend to explore the performance of our proposed service forecasting framework when compared to the performances predicted by other two service forecasting methods; one is traditional CBR based forecasting model and the other is the existing service forecasting model used by Company A. We ran each service forecasting 144 times; each time, input data were randomly sampled for each service forecasting framework. To evaluate accuracy of forecasting results, we used Mean Absolute Percentage Error (MAPE) as primary performance measure in our experiments. We conducted one-way ANOVA test with the 144 measurements of MAPE for three different service forecasting approaches. For example, the F-ratio of MAPE for three different service forecasting approaches is 67.25 and the p-value is 0.000. This means that the difference between the MAPE of the three different service forecasting approaches is significant at the level of 0.000. Since there is a significant difference among the different service forecasting approaches, we conducted Tukey's HSD post hoc test to determine exactly which means of MAPE are significantly different from which other ones. In terms of MAPE, Tukey's HSD post hoc test grouped the three different service forecasting approaches into three different subsets in the following order: our proposed approach > traditional CBR-based service forecasting approach > the existing forecasting approach used by Company A. Consequently, our empirical experiments show that our proposed approach outperformed the traditional CBR based forecasting model and the existing service forecasting model used by Company A. The rest of this paper is organized as follows. Section 2 provides some research background information such as summary of CBR and SOM. Section 3 presents a hybrid service forecasting framework based on Case-based Reasoning and Self-Organizing Maps, while the empirical evaluation results are summarized in Section 4. Conclusion and future research directions are finally discussed in Section 5.