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Gender Differences in Pain in Cancer Patients (성별에 따른 암환자의 통증 차이)

  • Kim, Hyun-Sook;Lee, So-Woo;Yun, Young-Ho;Yu, Su-Jeong;Heo, Dae-Seog
    • Journal of Hospice and Palliative Care
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    • v.4 no.1
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    • pp.14-25
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    • 2001
  • Purpose : To determine whether there exist gender differences in pain in Korean cancer patients and whether the depression and performance that are often expressed differently between men and women with cancer interact with pain. Method : The results of survey were collected from 140 in- and out-patients (78 male and 62 female) who had cancer treatment at one of the university hospital in Seoul for four months from February of 1999. The severity and interference of pain were examined with the self-reported survey based on Korean version of Brief Pain Inventory (BPI-K). Demographic and clinical information for all patient were compiled by reviewing their medical records, and the level of depression was examined with the Korean version of Beck Depression Inventory (BDI-K). Usual statistical methods, e.g., frequences, means and SDs were used to characterize the sample. The chi-square tests for categorical data and t-test for numerical data were used for group comparison. And the correlation between variables were performed using Pearson correlation coefficient. Resuts : 1) The mean scores of the worst pain for last 24-hours measured with the pain severity of BPI-K were 5.77 in male and 6.45 in female. The pain interference of BPI-K in men was in the order of mood (5.49), enjoy (5.36), and work (5.00), and in women were work (7.48), enjoy (7.16), and mood (6.53). 2) In pain severity, significant difference was found between men and women in the average pain for last 24-hours (t=-2.130, P=.035). In pain interference, significant difference was found between men and women in activity (t=-2.450, P=.015), mood (t=-2,321, P=.022), walk (t=-2.762, P=.007), work (t=-4.946, P=.000), relate (t=-2.595, P=.010), sleep (t=-2.071, P=.040), enjoy (t=-3.198, P=.001). 3) It was found that the items of pain and depression are significantly correlated in men but not in women. Men also exhibited higher correlation in the items of pain and performance status than women. Conclusions : Women report significantly greater average pain for last 24-hours and for all items of pain interference than men. Pain and depression are significantly correlated in men. The results of this study suggest that gender differences in pain should be considered for planning effective pain management program.

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The Content and Risk Assessment of Heavy Metals in Herbal Pills (유통 환제의 유해 중금속 함량 및 위해도 평가)

  • Lee, Sung-Deuk;Lee, Young-Ki;Kim, Moo-Sang;Park, Seok-Ki;Kim, Yeon-Sun;Chae, Young-Zoo
    • Journal of Food Hygiene and Safety
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    • v.27 no.4
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    • pp.375-387
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    • 2012
  • The objective of this study is investigation of contamination levels and assessment of health risk effects of heavy metals in herbal pills. 31 Items and 93 samples were obtained for this investigation from major herbal medicine producing areas, herbal markets and on-line supermarkets from Jan to Jun in 2010. Inductively coupled plasma mass spectrometer method was conducted for the quantitative analysis of Pb, Cd and As. In addition, the mercury analyzer system was conducted for that of Hg without sample digestion. The average contents of heavy metals in samples were as follows : 0.87 mg/kg for Pb, 0.08 mg/kg for Cd, 2.87 mg/kg for As and 0.16 mg/kg for Hg, respectively. In addition, the average contents of heavy metals in different parts of plants, including cortex, fructus, herba, radix, seed, algae and others were 0.63 mg/kg, 3.94 mg/kg, 1.42 mg/kg, 1.05 mg/kg, 0.16 mg/kg, 22.31 mg/kg and 10.17 mg/kg, respectively. After the estimations of dietary exposure, the acceptable daily intake (ADI), the average daily dose (ADD), the provisional tolerable weekly intake (PTWI) and the relative hazard of heavy metals were evaluated. As the results, the relative hazards compared to PTWI in samples were below the recommended standard of JECFA as Pb 3.1%, Cd 0.9%, Hg 0.5%. Cancer risks through slope factor (SF) by Ministry of Environment Republic Korea and Environmental Protection Agency was $4.24{\times}10^{-7}$ for Pb and $3.38{\times}10^{-4}$ for As (assuming that the total arsenic content was equal to the inorganic arsenic). Based on our results, possible Pb-induced cancer risks in herbal pills according to parts used including cortex, fructus, herba, radix, seed, algae and others were $1.95{\times}10^{-7}$, $1.45{\times}10^{-6}$, $2.14{\times}10^{-7}$, $6.27{\times}10^{-7}$, $1.99{\times}10^{-8}$, $3.61{\times}10^{-7}$ and $9.64{\times}10^{-8}$, respectively. Possible As-induced cancer risks in herbal pills by parts used including cortex, fructus, herba, radix, seed, algae and others were $1.54{\times}10^{-5}$, $7.24{\times}10^{-5}$, $1.23{\times}10^{-4}$, $2.02{\times}10^{-5}$, $3.25{\times}10^{-6}$, $2.18{\times}10^{-3}$ and $5.67{\times}10^{-6}$ respectively. Taken together, these results indicate that the majority of samples except for some samples with relative high contents of heavy metals were safe.

A Study on the Safety of Mycotoxins in Grains and Commonly Consumed Foods (곡류 등 다소비 식품 중 곰팡이독소 안전성 조사 연구)

  • Kim, Jae-Kwan;Kim, Young-Sug;Lee, Chang-Hee;Seo, Mi Young;Jang, Mi Kyung;Ku, Eun-Jung;Park, Kwang-Hee;Yoon, Mi-Hye
    • Journal of Food Hygiene and Safety
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    • v.32 no.6
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    • pp.470-476
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    • 2017
  • The purpose of this study was to investigate and evaluate the safety of the grains, nut products, beans and oilseeds being sold in Gyeonggi province by analyzing mycotoxins. A multi-mycotoxins analysis method based on LC-MS/MS was validated and applied for the determination of eight mycotoxins, including aflatoxins ($B_1$, $B_2$, $G_1$ and $G_2$), fumonisins ($B_1$, $B_2$), zearalenone and ochratoxcin A in 134 samples. The limit of detection (LOD) and limit of quantitation (LOQ) for the eight mycotoxins ranged from 0.14 to $8.25{\mu}g/kg$ and from 1.08 to $7.21{\mu}g/kg$, respectively. Recovery rates of mycotoxins were determined in the range of 61.1 to 97.5% with RSD of 1.0~14.5% (n=3). Fumonisin $B_1$, $B_2$, zearalenone, and ochratoxin A were detected in 22 samples, indicating that 27% of grains, 12.5% of beans and 11.8% of oilseeds were contaminated. Fumonisin and zearalenone were detected simultaneously in 2 adlays and 3 sorghums. Fumonisin $B_1$ and $B_2$ were detected simultaneously in most samples whereas fumonisin $B_1$ was detected in 1 adlay, 1 millet and 1 sesame sample. The average detected amount of fumonisin was $49.3{\mu}g/kg$ and $10.1{\mu}g/kg$ for grains and oilseeds, respectively. The average detected amount of zearalenone was $1.9{\mu}g/kg$ and $1.5{\mu}g/kg$ for grains and beans, respectively. In addition, the average amount of ochratoxin A was $0.08{\mu}g/kg$ for grains. The calculated exposure amounts of fumonisin, zeralenone and ochratoxin A for grains, beans and oilseeds were below the PMTDI/PTWI.

Chromaticity and Brown Pigment Patterns of Soy Sauce and UHYUKJANG, Korean Traditional Fermented Soy Sauce (간장과 어육장의 색도 및 갈색색소 패턴)

  • Kim, Ji-Sang;Moon, Gap-Soon;Lee, Young-Soon
    • Korean journal of food and cookery science
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    • v.22 no.5 s.95
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    • pp.642-649
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    • 2006
  • The browning of soy sauce is caused by the reaction of amino-carbonyl between amino-compounds and reducing sugar. Only a few studies have investigated the formation of melanoidins in UHYUKJANG. The objectives of this study were to analyze the brown pigment of UHYUKJANG and to investigate the characteristics of UHYUKJANG in comparison with soy sauce and model melanoidins. The samples were ripened for 0, 60, 120, 180, 240, 300 and 360 days at 4$^{\circ}C$ and 20$^{\circ}C$. The pH, absorbance at 420 nm absorbance ratio of 400 to 500 nm and UV-VIS spectra as an index of color intensity were measured. Additionally, L, a and b values of the samples and the amount of 3-Deoxyglucosone(3DG) in the samples were measured. The pH of both soy sauce (from 6.26 to 5.52) and UHYUKJANG (from 6.13 to 5.11) rapidly decreased during the first 60 days of aging and was also affected by storage temperature. The absorbance of samples at 420 nm increased during the aging process, reaching its maximum after 180 days, regardless of sample and temperature. On the other hand, the intensity of brown color in the samples increased with increasing aging period according to the results of absorbance ratio (soy sauce: 1.37 to 5.29, UHYUKJANG: 1.37 to 5.02). The L value of soy sauce increased during the aging process and was maximized after 240 days at 4$^{\circ}C$ and 180 days at 20$^{\circ}C$, but decreased thereafter. There was no significant difference in L value of UHYUKJANG, regardless of aging period and temperature. On the other hand, the b value did not reveal any significant change during aging, but the a value increased until 120 days of aging in the other samples except for UHYUKJANG at 20$^{\circ}C$. The average amount of 3DG separated from soy sauce was 5.65 mg%, and from UHYUKJANG was 3.74 mg%. These results indicated that the browning of UHYUKJANG was also caused by melanoidins produced by the reaction of amino-carbonyl during the fermentation process.

Microbiological Studies on Feed Supplements (사료첨가제(飼料添加劑)의 미생물오염(微生物汚染)에 관(關)하여)

  • Park, Su Kyung;Tak, Ryun Bin
    • Current Research on Agriculture and Life Sciences
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    • v.4
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    • pp.132-140
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    • 1986
  • Eighty one products from 36 kinds of vitamin and mineral feed supplement collected during August, 1984 to February, 1985 were examined for microbiological contamination. In addition, 83 strains of coliform isolated from the samples were tested for the resistance to 8 kinds of antimicrobial drugs and distribution of R plasmid. General bacteria were detected in all of samples tested. Bacterial population was varied from less than 10 per gram of the sample to 1,400,000 per gram and 34 (42%) of 81 samples were contaminated with 100 to 1,000 cells per gram. Coliform isolation, which was more frequent in samples with larger number of general bacteria, was possible in 14 (17.3%) out of 81 samples tested and 6 (33.3%) out of 18 companies were coliform positive in their products. Forty one (49.4%) out of 83 coliform isolates were fecal coliform. The frequency of resistant strains was the highest to sulfadimethoxine (Sa) with 92.8% and followed by streptomycin (Sm, 67.5%), tetracycline (Tc, 50.6%), kanamycin (Km, 26.5%), chloramphenicol (Cm, 18.1%) and ampicillin (Am, 15.7%). No strain was resistant to nalidixic acid (Na) and gentamicin (Gm). The resistance frequency of fecal coliform strains were higher compare to non-fecal coliform strains. There were minimum inhibitory concentration (MIC) of $3,200{\mu}g/m{\ell}$ or higher in 7 strains to Am, 3 to Sm and 3 to Km, and 70 strains had MIC of $1,600{\mu}g/m{\ell}$ of higher to Sa while Tc had MICs from $1.6{\mu}g/m{\ell}$ to $400{\mu}g/m{\ell}$. All strains had MICs of $6.3{\mu}g/m{\ell}$ of lower to Na and $3.1{\mu}g/m{\ell}$ of lower to Gm. Seventy nine (95.2%) of 83 strains were resistant to one or more drugs tested. The most frequent resistance patterns were SaSm (14.5%) and followed by SaSmTc(12%), SaSmTcKm(8.4%) SaTc (8.4%) and SaSmKm (7.2%) ; total 19 different patterns were noted. Thirty two (40.5%) of 79 resistant strains were transferred all of a part of their resistance to Escherichia coli ML 1410. The frequency of transferable resistance was high in Am (100%) and Cm (80%) while low in Tc (38.1%), Sa (18.2%), Sm (17.9%) and Km (4.5%).

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Development of a Simultaneous Analytical Method for Determination of Insecticide Broflanilide and Its Metabolite Residues in Agricultural Products Using LC-MS/MS (LC-MS/MS를 이용한 농산물 중 살충제 Broflanilide 및 대사물질 동시시험법 개발)

  • Park, Ji-Su;Do, Jung-Ah;Lee, Han Sol;Park, Shin-min;Cho, Sung Min;Kim, Ji-Young;Shin, Hye-Sun;Jang, Dong Eun;Jung, Yong-hyun;Lee, Kangbong
    • Journal of Food Hygiene and Safety
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    • v.34 no.2
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    • pp.124-134
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    • 2019
  • An analytical method was developed for the determination of broflanilide and its metabolites in agricultural products. Sample preparation was conducted using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method and LC-MS/MS (liquid chromatograph-tandem mass spectrometer). The analytes were extracted with acetonitrile and cleaned up using d-SPE (dispersive solid phase extraction) sorbents such as anhydrous magnesium sulfate, primary secondary amine (PSA) and octadecyl ($C_{18}$). The limit of detection (LOD) and quantification (LOQ) were 0.004 and 0.01 mg/kg, respectively. The recovery results for broflanilide, DM-8007 and S(PFP-OH)-8007 ranged between 90.7 to 113.7%, 88.2 to 109.7% and 79.8 to 97.8% at different concentration levels (LOQ, 10LOQ, 50LOQ) with relative standard deviation (RSD) less than 8.8%. The inter-laboratory study recovery results for broflanilide and DM-8007 and S (PFP-OH)-8007 ranged between 86.3 to 109.1%, 87.8 to 109.7% and 78.8 to 102.1%, and RSD values were also below 21%. All values were consistent with the criteria ranges requested in the Codex guidelines (CAC/GL 40-1993, 2003) and the Food and Drug Safety Evaluation guidelines (2016). Therefore, the proposed analytical method was accurate, effective and sensitive for broflanilide determination in agricultural commodities.

Evaluation of Varietal Difference and Environmental Variation for Some Characters Related to Source and Sink in the Rice Plants (벼의 Source 및 Sink형질의 품종간차이와 환경변이의 평가)

  • Choi, Hae-Chun;Kwon, Yong-Woong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.30 no.4
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    • pp.460-470
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    • 1985
  • Experiments were carried out to evaluate the standard gravity in determining potential kernel size and to determine the effective sampling way by analyzing intra - and inter - plant variations for some source and sink characters using eleven semi-dwarf indica and three japonica cultivars including four semi-dwarf indica nearisogenic lines. Also, additional experiments were conducted to understand yearly variation and variety x year interaction effects for ten characters related to source and sink and to characterize the varietal difference of pre- and post-heading self-competition employing three parental varieties and their F$\sub$5/ progenies in 1982 and 1983. It is desirable to determine the potential kernel size by average kernel wight of rice grains showing above 1.15 specific gravity. There was significant difference in leaf area per tiller, spikelets and sink capacity per panicle among vigorous, intermediate and inferior tillers classified by differentiated order and vigorousness. Although it was difficult to find out any significant difference in grain-fill ratio, ratio of perfectly ripened grain, potential kernel size and sink/source ratio between vigorous and intermediate tillers, there was big difference between them and inferior one. The coefficients of variation within each tiller-group for some characters related to source and sink were larger with the order of vigorous tillers < intermediate one '||'&'||'lt; inferior one, and the average heritability of all characters, evaluated by the ratio of varietal variance (equation omitted) to total variance (equation omitted), were higher with the order of inferior tillers '||'&'||'lt; intemediate one '||'&'||'lt; superior one. Therefore, it is desirable to sample the vigorous tillers to represent the varietal difference of these traits. '82-'83 year variations of three parental cultivars were significant for all traits except for leaf area/tiller, panicles/hill, leaf area index and rough rice yield. The characters showing highly significant variance of variety x year interaction were growth duration from transplanting to heading, leaf area/tiller, sink/source ratio, sink capacity/panicle and grain yield. Generalized yearly response of three parental varieties (Suweon 264, Raegyeong, IR1317-70-l) and their F$\sub$5/ progenies on the 1st and 2nd principal components extracted from ten source and sink characters generally exhibited reduction in both source and sink. However, there were diverse variety x year interactions such as progenies showing similar reaction with their parents and intermediate or recombinational yearly response with little or considerable yearly movement on the four-dimensional planes of the two upper principal components between 1982 and 1983. Sink characters revealing highly significant border effect were grain-fill ratio, spikelets and sink capacity per panicle. Among them the latter two especially showed significant variety x border effect interaction. Self-competition characterized by relative weakness of inside plant's sink characters compared to the border one was more severe during the reproductive stage before heading than maturing stage. Though the larger sink capacity per panicle generally disclosed the severer self-competition, some lines (like Suweon 264) revealed severe self-competition with small sink capacity while a few others showed tender self-competition in spite of big sink capacity per panicle.

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Evaluating the usefulness of BinkieRTTM (oral positioning stent) for Head and Neck Radiotherapy (두경부암 환자 방사선 치료 시 BinkieRTTM(구강용 고정장치)에 대한 유용성 평가)

  • GyeongJin Lee;SangJun Son;GyeongDal Lim;ChanYong Kim;JeHee Lee
    • The Journal of Korean Society for Radiation Therapy
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    • v.34
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    • pp.21-30
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    • 2022
  • Purpose: The purpose of this study is to evaluate the effectiveness of oral positioning stent, the BinkieRTTM in radiation treatment for head and neck cancer patients in terms of tongue positions reproducibility, tongue doses and material properties. Materials and Methods: 24 cases using BinkieRTTM during radiation treatments were enrolled. The tongue was contoured on planning CT and CBCT images taken every 3 days during treatment, and then the DSC and center of tongue shift values were analyzed to evaluate the reproducibility of the tongue. The tongue dose was compared in terms of dose distribution when using BinkieRTTM and different type of oral stents (mouthpiece, paraffin wax). Randomly selected respective 10 patients were measured tongue doses of initial treatment plan for nasal cavity and unilateral parotid cancer. Finally, In terms of material evaluation, HU and relative electron density were identified in RTPS. Results: As a result of DSC analysis, it was 0.8 ± 0.07, skewness -0.8, kurtosis 0.61, and 95% CI was 0.79~0.82. To analyze the deviation of the central tongue shift during the treatment period, a 95% confidence interval for shift in the LR, SI, and AP directions were indicated, and a one-sample t-test for 0, which is an ideal value in the deviation(n=144). As a result of the t-test, the mean and SD in the LR and SI directions were 0.01 ± 0.14 cm (p→.05), 0.03 ± 0.25 cm (p→.05), and -0.08 ± 0.25 cm (p ←.05) in the AP direction. In the case of unilateral parotid cancer patients, the Dmean to the tongue of patients using BinkieRTTM was 16.92% ± 3.58% compared to the prescribed dose, and 23.99% ± 10.86% of patients with Paraffin Wax, indicating that the tongue dose was relatively lower when using BinkieRTTM (p←.05). On the other hand, among nasal cavity cancer patients, the Dmean of tongue dose for patients who used BinkieRTTM was 4.4% ± 5.6%, and for those who used mouthpiece, 5.9% ± 6.8%, but it was not statistically significant (p→.05). The relative electron density of Paraffin Wax, BinkieRTTM and Putty is 0.94, 0.99, 1.26 and the mass density is 0.95, 0.99 and 1.32 (g/cc), Transmission Factor is 0.99, 0.98, 0.96 respectively. Conclusion: The result of the tongue DSC analysis over the treatment period was about 0.8 and Deviation of the center of tongue shifts were within 0.2 cm, the reproducibility was more likely excellent. In the case of unilateral head and neck cancer patients, it was found that the use of BinkieRTTM rather than Paraffin Wax or Putty can reduce the unnecessary dose irradiated to the tongue. This study might be useful to understand of BinkieRTTM's properties and advantages. And also it could be another considered option as oral stent to keep the reproducibility of tongue and reducing dose during head and neck radiation treatments.

A Study on the Market Structure Analysis for Durable Goods Using Consideration Set:An Exploratory Approach for Automotive Market (고려상표군을 이용한 내구재 시장구조 분석에 관한 연구: 자동차 시장에 대한 탐색적 분석방법)

  • Lee, Seokoo
    • Asia Marketing Journal
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    • v.14 no.2
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    • pp.157-176
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    • 2012
  • Brand switching data frequently used in market structure analysis is adequate to analyze non- durable goods, because it can capture competition between specific two brands. But brand switching data sometimes can not be used to analyze goods like automobiles having long term duration because one of main assumptions that consumer preference toward brand attributes is not changed against time can be violated. Therefore a new type of data which can precisely capture competition among durable goods is needed. Another problem of using brand switching data collected from actual purchase behavior is short of explanation why consumers consider different set of brands. Considering above problems, main purpose of this study is to analyze market structure for durable goods with consideration set. The author uses exploratory approach and latent class clustering to identify market structure based on heterogeneous consideration set among consumers. Then the relationship between some factors and consideration set formation is analyzed. Some benefits and two demographic variables - age and income - are selected as factors based on consumer behavior theory. The author analyzed USA automotive market with top 11 brands using exploratory approach and latent class clustering. 2,500 respondents are randomly selected from the total sample and used for analysis. Six models concerning market structure are established to test. Model 1 means non-structured market and model 6 means market structure composed of six sub-markets. It is exploratory approach because any hypothetical market structure is not defined. The result showed that model 1 is insufficient to fit data. It implies that USA automotive market is a structured market. Model 3 with three market structures is significant and identified as the optimal market structure in USA automotive market. Three sub markets are named as USA brands, Asian Brands, and European Brands. And it implies that country of origin effect may exist in USA automotive market. Comparison between modal classification by derived market structures and probabilistic classification by research model was conducted to test how model 3 can correctly classify respondents. The model classify 97% of respondents exactly. The result of this study is different from those of previous research. Previous research used confirmatory approach. Car type and price were chosen as criteria for market structuring and car type-price structure was revealed as the optimal structure for USA automotive market. But this research used exploratory approach without hypothetical market structures. It is not concluded yet which approach is superior. For confirmatory approach, hypothetical market structures should be established exhaustively, because the optimal market structure is selected among hypothetical structures. On the other hand, exploratory approach has a potential problem that validity for derived optimal market structure is somewhat difficult to verify. There also exist market boundary difference between this research and previous research. While previous research analyzed seven car brands, this research analyzed eleven car brands. Both researches seemed to represent entire car market, because cumulative market shares for analyzed brands exceeds 50%. But market boundary difference might affect the different results. Though both researches showed different results, it is obvious that country of origin effect among brands should be considered as important criteria to analyze USA automotive market structure. This research tried to explain heterogeneity of consideration sets among consumers using benefits and two demographic factors, sex and income. Benefit works as a key variable for consumer decision process, and also works as an important criterion in market segmentation. Three factors - trust/safety, image/fun to drive, and economy - are identified among nine benefit related measure. Then the relationship between market structures and independent variables is analyzed using multinomial regression. Independent variables are three benefit factors and two demographic factors. The result showed that all independent variables can be used to explain why there exist different market structures in USA automotive market. For example, a male consumer who perceives all benefits important and has lower income tends to consider domestic brands more than European brands. And the result also showed benefits, sex, and income have an effect to consideration set formation. Though it is generally perceived that a consumer who has higher income is likely to purchase a high priced car, it is notable that American consumers perceived benefits of domestic brands much positive regardless of income. Male consumers especially showed higher loyalty for domestic brands. Managerial implications of this research are as follow. Though implication may be confined to the USA automotive market, the effect of sex on automotive buying behavior should be analyzed. The automotive market is traditionally conceived as male consumers oriented market. But the proportion of female consumers has grown over the years in the automotive market. It is natural outcome that Volvo and Hyundai motors recently developed new cars which are targeted for women market. Secondly, the model used in this research can be applied easier than that of previous researches. Exploratory approach has many advantages except difficulty to apply for practice, because it tends to accompany with complicated model and to require various types of data. The data needed for the model in this research are a few items such as purchased brands, consideration set, some benefits, and some demographic factors and easy to collect from consumers.

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An Exploratory Study on the Competition Patterns Between Internet Sites in Korea (한국 인터넷사이트들의 산업별 경쟁유형에 대한 탐색적 연구)

  • Park, Yoonseo;Kim, Yongsik
    • Asia Marketing Journal
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    • v.12 no.4
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    • pp.79-111
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    • 2011
  • Digital economy has grown rapidly so that the new business area called 'Internet business' has been dramatically extended as time goes on. However, in the case of Internet business, market shares of individual companies seem to fluctuate very extremely. Thus marketing managers who operate the Internet sites have seriously observed the competition structure of the Internet business market and carefully analyzed the competitors' behavior in order to achieve their own business goals in the market. The newly created Internet business might differ from the offline ones in management styles, because it has totally different business circumstances when compared with the existing offline businesses. Thus, there should be a lot of researches for finding the solutions about what the features of Internet business are and how the management style of those Internet business companies should be changed. Most marketing literatures related to the Internet business have focused on individual business markets. Specifically, many researchers have studied the Internet portal sites and the Internet shopping mall sites, which are the most general forms of Internet business. On the other hand, this study focuses on the entire Internet business industry to understand the competitive circumstance of online market. This approach makes it possible not only to have a broader view to comprehend overall e-business industry, but also to understand the differences in competition structures among Internet business markets. We used time-series data of Internet connection rates by consumers as the basic data to figure out the competition patterns in the Internet business markets. Specifically, the data for this research was obtained from one of Internet ranking sites, 'Fian'. The Internet business ranking data is obtained based on web surfing record of some pre-selected sample group where the possibility of double-count for page-views is controlled by method of same IP check. The ranking site offers several data which are very useful for comparison and analysis of competitive sites. The Fian site divides the Internet business areas into 34 area and offers market shares of big 5 sites which are on high rank in each category daily. We collected the daily market share data about Internet sites on each area from April 22, 2008 to August 5, 2008, where some errors of data was found and 30 business area data were finally used for our research after the data purification. This study performed several empirical analyses in focusing on market shares of each site to understand the competition among sites in Internet business of Korea. We tried to perform more statistically precise analysis for looking into business fields with similar competitive structures by applying the cluster analysis to the data. The research results are as follows. First, the leading sites in each area were classified into three groups based on averages and standard deviations of daily market shares. The first group includes the sites with the lowest market shares, which give more increased convenience to consumers by offering the Internet sites as complimentary services for existing offline services. The second group includes sites with medium level of market shares, where the site users are limited to specific small group. The third group includes sites with the highest market shares, which usually require online registration in advance and have difficulty in switching to another site. Second, we analyzed the second place sites in each business area because it may help us understand the competitive power of the strongest competitor against the leading site. The second place sites in each business area were classified into four groups based on averages and standard deviations of daily market shares. The four groups are the sites showing consistent inferiority compared to the leading sites, the sites with relatively high volatility and medium level of shares, the sites with relatively low volatility and medium level of shares, the sites with relatively low volatility and high level of shares whose gaps are not big compared to the leading sites. Except 'web agency' area, these second place sites show relatively stable shares below 0.1 point of standard deviation. Third, we also classified the types of relative strength between leading sites and the second place sites by applying the cluster analysis to the gap values of market shares between two sites. They were also classified into four groups, the sites with the relatively lowest gaps even though the values of standard deviation are various, the sites with under the average level of gaps, the sites with over the average level of gaps, the sites with the relatively higher gaps and lower volatility. Then we also found that while the areas with relatively bigger gap values usually have smaller standard deviation values, the areas with very small differences between the first and the second sites have a wider range of standard deviation values. The practical and theoretical implications of this study are as follows. First, the result of this study might provide the current market participants with the useful information to understand the competitive circumstance of the market and build the effective new business strategy for the market success. Also it might be useful to help new potential companies find a new business area and set up successful competitive strategies. Second, it might help Internet marketing researchers take a macro view of the overall Internet market so that make possible to begin the new studies on overall Internet market beyond individual Internet market studies.

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