• Title/Summary/Keyword: Minimum Variance

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The Speaker Recognition System using the Pitch Alteration (피치변경을 이용한 화자인식 시스템)

  • Jung JongSoon;Bae MyungJin
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.115-118
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    • 2002
  • Parameters used in a speaker recognition system are desirable expressing speaker's characteristics filly and have in a speech. That is to say, if inter-speaker than intra-speaker variance a big characteristic, it is useful to distinguish between speakers. Also, to make minimum error between speakers, it is required the improved recognition technology as well as the distinguishing characteristics. When we see the result of recent simulation performance, we obtain more exact performance by using dynamic characteristics and constant characteristics by a speaking habit. Therefore we suggest it to solve this problem as followings. The prosodic information is used by a characteristic vector of speech. Characteristics vector generally using in speaker recognition system is a modeling spectrum information and is working for a high performance in non-noise circumstance. However, it is found a problem that characteristic vector is distorted in noise circumstance and it makes a reduction of recognition rate. In this paper, we change pitch line divided by segment which can estimate a dynamic characteristic and it is used as a recognition characteristic. we confirmed that the dynamic characteristic is very robust in noise circumstance with a simulation. We make a decision of acceptance or rejection by comparing test pattern and recognition rate using the proposed algorithm has more improvement than using spectrum and prosodic information. Especially stational recognition rate can be obtained in noise circumstance through the simulation.

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Derivation of Asymptotic Formulas for the Signal-to-Noise Ratio of Mismatched Optimal Laplacian Quantizers (불일치된 최적 라플라스 양자기의 신호대잡음비 점근식의 유도)

  • Na, Sang-Sin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.5C
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    • pp.413-421
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    • 2008
  • The paper derives asymptotic formulas for the MSE distortion and the signal-to-noise ratio of a mismatched fixed-rate minimum MSE Laplacian quantizer. These closed-form formulas are expressed in terms of the number N of quantization points, the mean displacement $\mu$, and the ratio $\rho$ of the standard deviation of the source to that for which the quantizer is optimally designed. Numerical results show that the principal formula is accurate in that, for rate R=$log_2N{\geq}6$, it predicts signal-to-noise ratios within 1% of the true values for a wide range of $\mu$, and $\rho$. The new findings herein include the fact that, for heavy variance mismatch of ${\rho}>3/2$, the signal-to-noise ratio increases at the rate of $9/\rho$ dB/bit, which is slower than the usual 6 dB/bit, and the fact that an optimal uniform quantizer, though optimally designed, is slightly more than critically mismatched to the source. It is also found that signal-to-noise ratio loss due to $\mu$ is moderate. The derived formulas can be useful in quantization of speech or music signals, which are modeled well as Laplacian sources and have changing short-term variances.

A Study of Post-processing Methods of Clustering Algorithm and Classification of the Segmented Regions (클러스터링 알고리즘의 후처리 방안과 분할된 영역들의 분류에 대한 연구)

  • Oh, Jun-Taek;Kim, Bo-Ram;Kim, Wook-Hyun
    • The KIPS Transactions:PartB
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    • v.16B no.1
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    • pp.7-16
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    • 2009
  • Some clustering algorithms have a problem that an image is over-segmented since both the spatial information between the segmented regions is not considered and the number of the clusters is defined in advance. Therefore, they are difficult to be applied to the applicable fields. This paper proposes the new post-processing methods, a reclassification of the inhomogeneous clusters and a region merging using Baysian algorithm, that improve the segmentation results of the clustering algorithms. The inhomogeneous cluster is firstly selected based on variance and between-class distance and it is then reclassified into the other clusters in the reclassification step. This reclassification is repeated until the optimal number determined by the minimum average within-class distance. And the similar regions are merged using Baysian algorithm based on Kullbeck-Leibler distance between the adjacent regions. So we can effectively solve the over-segmentation problem and the result can be applied to the applicable fields. Finally, we design a classification system for the segmented regions to validate the proposed method. The segmented regions are classified by SVM(Support Vector Machine) using the principal colors and the texture information of the segmented regions. In experiment, the proposed method showed the validity for various real-images and was effectively applied to the designed classification system.

Bioequivalence of Podox Tablet to Banan Tablet (Cefpodoxime Proxetil 100 mg) (바난 정(세프포독심 프록세틸 100mg)에 대한 포독스 정의 생물학적 동등성)

  • Cho, Seong-Wan;Lee, Ji-Hye;Song, Il-Yong;Lee, Sang-Kil;Cha, Young-Joo;Choi, Young-Wook
    • Journal of Pharmaceutical Investigation
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    • v.29 no.3
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    • pp.241-245
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    • 1999
  • Bioequivalence study of two cefpodoxime preparations, the test drug ($Banan^{\circledR}$: Hanil Pharmaceutical Co., Ltd.) and the reference drug ($Podox^{\circledR}$: Chong Kun Dang Pharmaceutical Co., Ltd.), was conducted according to the guidelines of Korea Food and Drug Administration (KFDA). Sixteen healthy male volunteers, $23.8{\pm}2.13$ years old and $63.34{\pm}4.84kg$ of body weight in average, were divided randomly into two groups and administered the drug orally at the dose of 200 mg as cefpodoxime proxetil in a $2{\times}2$ crossover study. Plasma concentrations of cefpodoxime were analysed by HPLC method for 12 hr after administration. The $AUC_{0-12hr}$ was calculated by the linear trapezoidal rule method. The $C_{max}$, and $T_{max}$ were compiled directly from the plasma drug concentration-time data. Student's t-test indicated no significant differences between the formulations in these parameters. Analysis of variance (ANOVA) revealed that there were no differences in AUC, $C_{max}$, and $T_{max}$ between the formulations. The apparent differences between the formulations were far less than 20% (e.g., 4.31, 1.99 and 4.30% for AUC, $C_{max}$, and $T_{max}$, respectively). Minimum detectable differences (%) between the formulations at ${\alpha}=\;0.05$ and $1-{\beta}=\;0.8$ were less than 20% (e.g., 13.89, 13.88, and 16.97% for AUC, $C_{max}$, and $T_{max}$, respectively). The 90% confidence intervals for these parameters were also within ${\times}20%$ (e.g., $-5,58{\sim}14.20$, $-7.89{\sim}11.88$, and $-7.78{\sim}16.38%$ for AUC, $C_{max}$, and $T_{max}$, respectively). These results satisfied the bioequivalence criteria of KFDA guidelines, indicating that the two formulations of cefpodoxime were bioequivalent.

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Dental Hygiene Treatment Fear, Anxiety and Related Factors in Dental Patients (치과위생처치와 관련된 두려움, 불안 및 관련요인 -일부 치위생처치 환자를 대상으로-)

  • Cho, Myung-Sook
    • Journal of Korean society of Dental Hygiene
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    • v.6 no.4
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    • pp.419-436
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    • 2006
  • PURPOSE: The purpose of this study was to explore dental hygiene treatment fear and anxiety in dental patients. METHODS: The sample consisted of 466 dental patients who had received the dental hygiene treatment at 8 Dental Hospitals and Clinics in Daegu city between March and August 2006 studied. Dental hygienists recruited a questionnaire, which includes generalized anxiety sub-scale(4 items), specific fear sub-scale(5 items), distrust sub-scale(5 items), and catastrophic anxiety sub-scale(4 items). Minimum score is 1, and maximum score is 5. The research was designed to be a cross-sectional measured study. SAS statistical software was used for the analysis. The characteristics of the study sample were described by mean and standard deviation(SD) for continuous variables and by frequency and percentage for categorical variables. The Student's t-test and analysis of variance(ANOVA) were used to compare fear and anxiety score in demographic variables. A Pearson's correlation analysis was conducted for relationship among values of fear and anxiety for dental hygiene. Multiple regression analysis was performed to determine the factors associated with fear and anxiety related with dental hygiene. RESULTS: A total of 466 dental patients were analyzed, their average age${\pm}$SD was $37.7{\pm}12.9$ years(range: 15-79 yr). The mean value for dental hygiene fear and anxiety was 2.70(generalized anxiety 2.65, specific fear 2.93, distrust anxiety 2.72, and catastrophic anxiety 2.42, respectively). There was a statistically significant difference in gender(p<0.05), 2.81 for women was higher than 2.55 for men(p=.0000). The older we are, the higher fear and anxiety for dental hygiene treatment were. that is, under age of 20 years 2.49, 20 years 2.59, 30 years 2.69, 40 years 2.77, 50 years 2.88, 60 years 2.69, and over age of 70 2.45, respectively(p=.0321). Factors related to dental hygiene treatment fear and anxiety by multiple regressions were gender(${\square}$=0.18, p=0.0001), age(${\square}$=.07, p=.0058), and the time when visits dentist recently(${\square}$=.07, p=.0058). CONCLUSIONS: In conclusion, gender, age and the time when visits dentist recently were significantly associated with dental hygiene treatment fear and anxiety. We recommend that further research should investigate a dental hygiene treatment fear and anxiety by using more follow-up study.

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Evaluating the Predictability of Heat and Cold Damages of Soybean in South Korea using PNU CGCM -WRF Chain (PNU CGCM-WRF Chain을 이용한 우리나라 콩의 고온해 및 저온해에 대한 예측성 검증)

  • Myeong-Ju, Choi;Joong-Bae, Ahn;Young-Hyun, Kim;Min-Kyung, Jung;Kyo-Moon, Shim;Jina, Hur;Sera, Jo
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.24 no.4
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    • pp.218-233
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    • 2022
  • The long-term (1986~2020) predictability of the number of days of heat and cold damages for each growth stage of soybean is evaluated using the daily maximum and minimum temperature (Tmax and Tmin) data produced by Pusan National University Coupled General Circulation Model (PNU CGCM)-Weather Research and Forecasting (WRF). The Predictability evaluation methods for the number of days of damages are Normalized Standard Deviations (NSD), Root Mean Square Error (RMSE), Hit Rate (HR), and Heidke Skill Score (HSS). First, we verified the simulation performance of the Tmax and Tmin, which are the variables that define the heat and cold damages of soybean. As a result, although there are some differences depending on the month starting with initial conditions from January (01RUN) to May (05RUN), the result after a systematic bias correction by the Variance Scaling method is similar to the observation compared to the bias-uncorrected one. The simulation performance for correction Tmax and Tmin from March to October is overall high in the results (ENS) averaged by applying the Simple Composite Method (SCM) from 01RUN to 05RUN. In addition, the model well simulates the regional patterns and characteristics of the number of days of heat and cold damages by according to the growth stages of soybean, compared with observations. In ENS, HR and HSS for heat damage (cold damage) of soybean have ranged from 0.45~0.75, 0.02~0.10 (0.49~0.76, -0.04~0.11) during each growth stage. In conclusion, 01RUN~05RUN and ENS of PNU CGCM-WRF Chain have the reasonable performance to predict heat and cold damages for each growth stage of soybean in South Korea.

Photosynthetic Characteristics of Porphyra yezoensis Ueda Measured in situ by Diving Pulse-Amplitude Modulated (PAM) Fluorometry on the Southwestern Coast of the Korean Peninsula (남서해역에서 양식되는 방사무늬김(Porphyra yezoensis Ueda)의 Diving-PAM에 의한 광합성 특성)

  • Kim, Jeong Bae;Lee, Won-Chan;Kim, Hyung Chul;Choi, Hee-Gu;Park, Jung-Im;Cho, Yoonsik;Park, Hwan Hee
    • Korean Journal of Environmental Biology
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    • v.30 no.3
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    • pp.210-218
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    • 2012
  • The morphological characteristics, carbon and nitrogen concentrations, stable isotope values and photosynthetic rates of Porphyra yezoensis were studied at the main purple lavers production areas on southwestern coast of Korea. The morphological characteristics of leaf length, leaf width and weight of Porphyra blades were between 11.6~16.3 (average 13.8) cm, 4.6~6.3 (average 5.4) cm, $1.1{\sim}2.6(average\;1.86)g\;DW\;m^{-2}$, respectively. Photosynthetic pigment of Chl a concentration of Porphyra blades was between $2.18{\sim}17.77(average\;9.65)mg\;DW\;Chl\;a\;m^{-2}$. Carbon and nitrogen concentrations of Porphyra blades was between $201{\sim}317(average\;240)mg\;DW\;g^{-1}$, $39.8{\sim}50.0(average\;43.5)mg\;DW\;g^{-1}$ and C/N ratio 5.0~6.7 (average 5.5). The range of average ${\delta}^{13}C$ and ${\delta}^{15}N$ values of Porphyra blades was between - 25.6 to - 24.0 (average - 24.7)‰ for ${\delta}^{13}C$, and 1.3 to 4.1 (average 2.1)‰ for ${\delta}^{15}N$. Photosynthetic characteristics of seaweeds measured by pulse amplitude modulation (PAM) fluorometry was used as an indicator of photosynthetic activity. We use Diving-PAM fluorometry to examine photosynthetic rates of the seaweeds Porphyra yezoensis at each station. Maximum quantum yield of Porphyra blades was between 0.46~0.55 (average 0.52), the variance of the effective PS II maximum quantum yield of the station was broadly similar. Maximum relative electron transport rate (rETRmax) of Porphyra blades was between $4.71{\sim}5.84(average\;5.33){\mu}mol\;electrons\;m^{-2}\;s^{-1}$, the changes of maximum relative electron transport rate (rETRmax) of Porphyra yezoensis were similar to those of PS II maximum quantum yield. Photosynthetic efficiency (${\alpha}$) was between 0.027~0.045 (average 0.036). Minimum saturating irradiance ($E_k$) range was $139{\sim}180(average\;156){\mu}mol\;photons\;m^{-2}\;s^{-1}$. Minimum saturating irradiance ($E_k$) made a difference by station within the area on southwestern coast. Carbon and nitrogen concentrations and photosynthetic rates of Porphyra blades production areas on southwestern coast were broadly similar. The photosynthetic characteristics showed low photosynthetic rates because the low maximum quantum yields and low maximum relative electron transport rate.

평행식 진동탄환 암거 천공기의 연구 (IV)(V)-실기 설계 제작 및 보장실험-Development of Balanced-Type Oscillating Mole Drainer(IV)(V)

  • 김용환;이승규;서상용
    • Journal of Biosystems Engineering
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    • v.2 no.1
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    • pp.7-24
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    • 1977
  • This paper is the forth and fifth one of the study on balanced type oscillating mole drainer. In the light of the results from previous reports about the model tests, some design criteria were established and a prototype machine was set up for experimental purpose. Motion characteristics and functionof the each parts of the machine were checked and analyzed. After that, performance tests of the prototype machine were carried out in thefield. Obtained results are summarized as follows ; 1. Ten centimeter of the bullet diameter was determined so as to be able to attach it to the tractors with capacity of 30 PS to 40 PS. 2. To maintain the balance between the moments of the front shank and rear shank, the oscillating amplitude of the rear bullet was determined to be larger than that of the front bullet. At the same time , the oscillating direction of the rear bullet was designed with the inclines of ten to thirty degrees. 3. An octagonal dynamo transduced was developed for measuring the compressive force of the upper link is measuring the draft force of the machine. Acceptable linear relationship between forces and strain responses from O.D.T. was obtained. 4. Analysing the balancing mechanism of the acting part of the machine , it was found that the total draft force of the machine was equal to the difference between the sum of the draft force produced from the right and left side bending moments of the lower drawber and the compressive force on the upper link. 5. There are acceptable linear relationship between the strain and twisting moment by driving shaft, and between strain and shank moment. Above results enable us to carry out the field experiment with prototype machine. 6. When the test machine was used in the field, it was possible to reduce the oscillating acceleration by forty percent in average as compared it with the single bullet mole drainer. 7. When the test machine was used under the oscillating condition, the dratt torce was reduced by 27 percent to 59 percent as compared it with the test machine under non-oscillating condition, while the draft force was increased by 7 percent to 20 percent as compared it with the mole drainer having oscillating single bullet. The reasoning behind this fact was considered as the resistance force due to the rear shank and bullet. 8. As the amplitude and frequency of the bullet were increased, the torque was increased accordingly. This tendency could be varied with the various characteristics of the given soils. And the larger frequency and amplitute, the more increasing oscil\ulcornerlating power but decreasing draft brce were needed, and draft force was increased as the velocity was increased.9. When the amplitude of the rear bullet was designed to be larger than that of the front bullet, the minimum value of the moment was lowered and oscillating acceleration was reduced. And when the oscillating direction of the rear bullet was declined back\ulcornerwards, oscillating acceleration was increased along with the increasing angle of decli\ulcornernation. When the test machine was operated in high speed, the difference between maximum moments and minimum ones became narrow. This varying magnitude of moments appeared on the moment oscillogram seems to be correlated to the oscillating acceleration and draft force. 10. From the analysis of variance, it was found that those factors such as frequency, amplitude, and operating velocity significantly affected in the oscillating acceleration, the draft resistance, the torque, the moment, and the total power required. And interaction between frequency and amplitude affected in the oscillating acceleration. 11. Within the given situation of this study, the most preferable operating conditions of the test machine were 7 Hz in oscillating frequency, 0.54 m/sec in operating velocity, and 39.1 mm in oscillating amplitude of front and rear bullets. However, it is necessary to select the proper frequency and magnitude of oscillation depending on the soil properties of the field in which the mole drainer is practiced by use of a bal1nced type oscillating mole drainer. 12. It is recommended that a comparative study of the mole drainers would be performed in the near future using two separate balanced oscillating bullet with the one which is operated by oscillating the movable bullet in a single cylinder or other balanced type which may be single oscillating bullet with spring, damper or balancing weight, and that of thing. To expand the applicability of the balanced type oscillating mole drainer in practical use, it is suggested to develop a new mechanism which perform mole drain with vinyl pipe or filling material such as rice hull.

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The clinical study of acne patients (面疱 患者에 對한 臨床的 硏究)

  • Chae, Byeong-yoon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.11 no.1
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    • pp.251-268
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    • 1998
  • 125 Cases of Acne were treated by Acupuncture and Herb-med treatment during a three months duration from April 1996 to February 1998 in Kyung Hee Univ. Department of Ophthal, Otolaryngology. College of Oriental Medicine. We have observed the cases and the results as follows: 1. The age of average was 24.55 age : 21.91 in males, 24.55 in females. and in these, the gulf between males and females were showed statically significant diference. In the age of onset, averag was 16.96 age and mode was 18 age and male's average was 16.96 age, minimun was 11 age, maximum 40 age and female's average was 20.14 age, minimun was 10 age, maximum 40 age. and these were showed statically significant diference between males and females. 2. In the distribution of season, winter was the most with $37.8\%$ of out patients, the rest was similar to difference of each other. but there was clear difference between males and females. 3. In the duration of history, the average was 5.10 years and male's average was 5.13 years. on the other hand female's was 5.09 years but there is no any significant difference have a resemblance with each other. 4. In blood type, O type was the most with $35.20\%$ and there was in the order of A type was $26.40\%\;B\;type\;was\;23.20\%,\;AB\;type\;was\;15.20\%$ but these were not significant difference by the chi-tend and analysis of variance with total cases, males and females. 5. In select of the preference food, patients of the prefer worm food was $42.40\%\;and\;cool\;food\;was\;38.40\%,\;tepid\;food\;was\;24\%$ but these were no significant difference by the chi-test and ANOVA of each other. 6. the state of pulse classified into 11 type and average was 7.2 times, maximum was 29 times with Hyun Sae, at the same time, the female's average was 6.73 times, maximum was 27 times and male's average was 1.5 times. The result of test with each other, these were showed statically significant difference as compared total cases with males but there were not females ones. 7. In the frequency of the major cause, oversensitiveness was the most with $34.93\%$. secondly there was in order of indigestion $30.82\%$ and menstrual irregularity and menstruation pain $23.28\%$. constipation $10.96\%$ and these showed statically significant difference as compared the females with males on the result of test for difference with each other. 8. In frequency of the symptoms, itching was the most with $31.97\%$ and there was in order of nodule $20.49\%$, pustule $18.85\%,\;papule\;15.58\%,\;flare\;13.12\%$ and also these showed statically significant difference as compared the females with males 9. for the Distribution of acne region, face was the most with $64.06\%$ and there was in order of back $14.29\%,\;upper-chest\;11.69\%,\;neck\;7.79\%$ and there was no significant difference as compared total cases with males and females. 10. Acne applied 30 prescription to 4 weeks and over and 20 weeks and over was $23.3\%$, 30 weeks and over was $16.67\%$ and average of administration duration were 4.2 weeks(male's average 5.78, maximum 96 weeks and female's average 3.85, maximum 23 weeks) maximum was 96 weeks, minimum was 1 week. 11. In the acupuncture treatment, $96.6\%$ applied to acupuncture and average was 5.44 times, maximum 46 times, minimum 1 time(male's average 4.64, female's 5.62) but these were not any significant differeence. 12. for the medication, author made a investigation and comparison between control group with treated group in order to observe for the therapeutic effect during the 1 month and 2, 3. From these results, we can see that acne was improved by the oriental treatment. in the 1 month, average of control group was 13.24 and treated group was 11.78. these showed statically significant decrease in P<0.02 as compared the treated group with control group. In the 2 months, average of control group was 13.43 and treated group was 9.03. these showed statically significant decrease in P<0.003 as compared the treated group with control group. In the 3 months, average of control group was 13.78 and treated group was 8.06. these showed statically significant decrease in P<0.008 as compared the treated group with control group.

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An Analysis of the Moderating Effects of User Ability on the Acceptance of an Internet Shopping Mall (인터넷 쇼핑몰 수용에 있어 사용자 능력의 조절효과 분석)

  • Suh, Kun-Soo
    • Asia pacific journal of information systems
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    • v.18 no.4
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    • pp.27-55
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    • 2008
  • Due to the increasing and intensifying competition in the Internet shopping market, it has been recognized as very important to develop an effective policy and strategy for acquiring loyal customers. For this reason, web site designers need to know if a new Internet shopping mall(ISM) will be accepted. Researchers have been working on identifying factors for explaining and predicting user acceptance of an ISM. Some studies, however, revealed inconsistent findings on the antecedents of user acceptance of a website. Lack of consideration for individual differences in user ability is believed to be one of the key reasons for the mixed findings. The elaboration likelihood model (ELM) and several studies have suggested that individual differences in ability plays an moderating role on the relationship between the antecedents and user acceptance. Despite the critical role of user ability, little research has examined the role of user ability in the Internet shopping mall context. The purpose of this study is to develop a user acceptance model that consider the moderating role of user ability in the context of Internet shopping. This study was initiated to see the ability of the technology acceptance model(TAM) to explain the acceptance of a specific ISM. According to TAM. which is one of the most influential models for explaining user acceptance of IT, an intention to use IT is determined by usefulness and ease of use. Given that interaction between user and website takes place through web interface, the decisions to accept and continue using an ISM depend on these beliefs. However, TAM neglects to consider the fact that many users would not stick to an ISM until they trust it although they may think it useful and easy to use. The importance of trust for user acceptance of ISM has been raised by the relational views. The relational view emphasizes the trust-building process between the user and ISM, and user's trust on the website is a major determinant of user acceptance. The proposed model extends and integrates the TAM and relational views on user acceptance of ISM by incorporating usefulness, ease of use, and trust. User acceptance is defined as a user's intention to reuse a specific ISM. And user ability is introduced into the model as moderating variable. Here, the user ability is defined as a degree of experiences, knowledge and skills regarding Internet shopping sites. The research model proposes that the ease of use, usefulness and trust of ISM are key determinants of user acceptance. In addition, this paper hypothesizes that the effects of the antecedents(i.e., ease of use, usefulness, and trust) on user acceptance may differ among users. In particular, this paper proposes a moderating effect of a user's ability on the relationship between antecedents with user's intention to reuse. The research model with eleven hypotheses was derived and tested through a survey that involved 470 university students. For each research variable, this paper used measurement items recognized for reliability and widely used in previous research. We slightly modified some items proper to the research context. The reliability and validity of the research variables were tested using the Crobnach's alpha and internal consistency reliability (ICR) values, standard factor loadings of the confirmative factor analysis, and average variance extracted (AVE) values. A LISREL method was used to test the suitability of the research model and its relating six hypotheses. Key findings of the results are summarized in the following. First, TAM's two constructs, ease of use and usefulness directly affect user acceptance. In addition, ease of use indirectly influences user acceptance by affecting trust. This implies that users tend to trust a shopping site and visit repeatedly when they perceive a specific ISM easy to use. Accordingly, designing a shopping site that allows users to navigate with heuristic and minimal clicks for finding information and products within the site is important for improving the site's trust and acceptance. Usefulness, however, was not found to influence trust. Second, among the three belief constructs(ease of use, usefulness, and trust), trust was empirically supported as the most important determinants of user acceptance. This implies that users require trustworthiness from an Internet shopping site to be repeat visitors of an ISM. Providing a sense of safety and eliminating the anxiety of online shoppers in relation to privacy, security, delivery, and product returns are critically important conditions for acquiring repeat visitors. Hence, in addition to usefulness and ease of use as in TAM, trust should be a fundamental determinants of user acceptance in the context of internet shopping. Third, the user's ability on using an Internet shopping site played a moderating role. For users with low ability, ease of use was found to be a more important factors in deciding to reuse the shopping mall, whereas usefulness and trust had more effects on users with high ability. Applying the EML theory to these findings, we can suggest that experienced and knowledgeable ISM users tend to elaborate on such usefulness aspects as efficient and effective shopping performance and trust factors as ability, benevolence, integrity, and predictability of a shopping site before they become repeat visitors of the site. In contrast, novice users tend to rely on the low elaborating features, such as the perceived ease of use. The existence of moderating effects suggests the fact that different individuals evaluate an ISM from different perspectives. The expert users are more interested in the outcome of the visit(usefulness) and trustworthiness(trust) than those novice visitors. The latter evaluate the ISM in a more superficial manner focusing on the novelty of the site and on other instrumental beliefs(ease of use). This is consistent with the insights proposed by the Heuristic-Systematic model. According to the Heuristic-Systematic model. a users act on the principle of minimum effort. Thus, the user considers an ISM heuristically, focusing on those aspects that are easy to process and evaluate(ease of use). When the user has sufficient experience and skills, the user will change to systematic processing, where they will evaluate more complex aspects of the site(its usefulness and trustworthiness). This implies that an ISM has to provide a minimum level of ease of use to make it possible for a user to evaluate its usefulness and trustworthiness. Ease of use is a necessary but not sufficient condition for the acceptance and use of an ISM. Overall, the empirical results generally support the proposed model and identify the moderating effect of the effects of user ability. More detailed interpretations and implications of the findings are discussed. The limitations of this study are also discussed to provide directions for future research.