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PubMed2006

Gabor-based kernel PCA with doubly nonlinear mapping for face recognition with a single face image.

In this paper, a novel Gabor-based kernel principal component analysis (PCA) with doubly nonlinear mapping is proposed for human face recognition. In our approach, the Gabor wavelets are used to extract facial features, then a doubly nonlinear mapping kernel PCA (DKPCA) is proposed to perform feature transformation and face recognition. The conventional kernel PCA nonlinearly maps an input image into a high-dimensional feature space in order to make the mapped features linearly separable. However, this method does not consider the structural characteristics of the face images, and it is difficult to determine which nonlinear mapping is more effective for face recognition. In this paper, a new method of nonlinear mapping, which is performed in the original feature space, is defined. The proposed nonlinear mapping not only considers the statistical property of the input features, but also adopts an eigenmask to emphasize those important facial feature points. Therefore, after this mapping, the transformed features have a higher discriminating power, and the relative importance of the features adapts to the spatial importance of the face images. This new nonlinear mapping is combined with the conventional kernel PCA to be called "doubly" nonlinear mapping kernel PCA. The proposed algorithm is evaluated based on the Yale database, the AR database, the ORL database and the YaleB database by using different face recognition methods such as PCA, Gabor wavelets plus PCA, and Gabor wavelets plus kernel PCA with fractional power polynomial models. Experiments show that consistent and promising results are obtained.

Algorithms↗
PubMed1999

Face-to-face diagnosis vs telediagnosis of pigmented skin tumors: a teledermoscopic study.

BACKGROUND: Teledermoscopy uses telecommunication technologies to transfer images of pigmented skin lesions, including clinical and anamnestic data, via e-mail to specialized centers for teleconsultation. DESIGN: Sixty-six pigmented skin lesions examined on a face-to-face basis in a skin lesion clinic in L'Aquila, Italy, were sent via e-mail on a standard-resolution color monitor for consultation at a university dermatology department in Graz, Austria. INTERVENTION: Digital photographs of the clinical and dermoscopic images of all pigmented tumors were taken with a stereomicroscope connected to a high-resolution video camera in Truevision advanced graphic array (Targa) format file and converted successively into a Joint Photographic Expert Group (PEG) format file. All lesions were excised surgically and diagnosed histopathologically. MAIN OUTCOME MEASURE: Diagnostic concordance between face-to-face diagnosis and telediagnosis. RESULTS: The diagnostic concordance was 60 (91%) of 66 cases. The number of correct telediagnoses was lower, but the difference was not statistically significant (Wilcoxon test, P = .10). The accuracy of the telediagnoses was not related to the quality of the images, but highly depended on the level of diagnostic difficulty of a given pigmented skin tumor (Spearman correlation, P= .01). CONCLUSION: Teleconsultation of clinical and dermoscopic images of skin tumors via e-mail provides a similar degree of diagnostic accuracy as face-to-face diagnosis.

Adolescent↗
PubMed2004

Comparison of skin biopsy triage decisions in 49 patients with pigmented lesions and skin neoplasms: store-and-forward teledermatology vs face-to-face dermatology.

OBJECTIVE: To determine the relative efficacy of store-and-forward teledermatology vs face-to-face dermatology consultations in triage decisions about the need for a biopsy of neoplastic skin changes. DESIGN: Prospective study of consecutive patients judged by an internist to require dermatologic consultation for a skin growth. SETTING: Private primary care and dermatology practices and an academic dermatology practice. PATIENTS: Patients requiring dermatology consultation for evaluation of skin growths. Patients were seen by a single primary care physician between July 10, 1998, and August 4, 2000. INTERVENTION: Digital photographs of skin growths were obtained by the primary care physician and evaluated by a teledermatologist. The patient was then seen face-to-face by a dermatologist. A biopsy was performed if either dermatologist favored biopsy. MAIN OUTCOME MEASURES: Decisions to perform a biopsy. Agreement between the dermatologists was assessed. RESULTS: Of the 49 patients with evaluable photographs, the face-to-face dermatologist and teledermatologist recommended a biopsy for the same 26 patients, yielding a sensitivity of the teledermatologist of 1.00 (95% confidence interval [CI], 0.87-1.00) and a specificity of 1.00 (95% CI, 0.85-1.00). The agreement between the dermatologists (kappa) was 1.00 (95% CI, 0.72-1.00). CONCLUSION: Store-and-forward teledermatology may provide an accurate and cost-effective method of determining whether skin growths in patients presenting to primary care physicians should undergo biopsy.

Biopsy↗
PubMed2007

Detection of memory impairment in the general population: screening by questionnaire and telephone compared to subsequent face-to-face assessment.

BACKGROUND: Development of efficient methods for identifying subjects with Mild Cognitive Impairment (MCI) from the general population is warranted, because these subjects represent an important group for (epidemiological) research purposes. OBJECTIVES: (1) To describe a two-step population screening for identifying adults with MCI from the general population for research purposes, by questionnaire and telephone; (2) to compare screening by telephone (method 1) to a subsequent face-to-face assessment (method 2). METHODS: In method 1, subjects with memory complaints were identified from the general population (n = 5491) by a postal questionnaire. Subsequently, cognitive status and memory were assessed in a telephone interview using the Telephone Interview for Cognitive Status and the Ten Word Learning Test. Next, subjects with MCI according to method 1 were subjected to a face-to-face assessment for method 2, in which cognitive status and memory were assessed using the Mini Mental State Examination (MMSE) and the Auditory Verbal Learning Test (AVLT). RESULTS: Two hundred and twenty-seven subjects completed both the telephone interview and the face-to-face assessment. Ninety-three subjects (41%) had MCI according to both methods. Seven subjects (3%) failed to meet MCI criteria according to method two because of an MMSE score <24; 127 subjects (56%) failed because of normal AVLT scores. CONCLUSION: (1) The two-step population screening was able to detect a considerable number of MCI-subjects in the general population; (2) agreement between both methods was moderate. Therefore, the method of recruiting subjects for (epidemiological) studies has to be taken into consideration when interpreting results of these studies.

Aged↗
PubMed1998

Decision Accuracy in Computer-Mediated versus Face-to-Face Decision-Making Teams.

Changes in the way organizations are structured and advances in communication technologies are two factors that have altered the conditions under which group decisions are made. Decisions are increasingly made by teams that have a hierarchical structure and whose members have different areas of expertise. In addition, many decisions are no longer made via strictly face-to-face interaction. The present study examines the effects of two modes of communication (face-to-face or computer-mediated) on the accuracy of teams' decisions. The teams are characterized by a hierarchical structure and their members differ in expertise consistent with the framework outlined in the Multilevel Theory of team decision making presented by Hollenbeck, Ilgen, Sego, Hedlund, Major, and Phillips (1995). Sixty-four four-person teams worked for 3 h on a computer simulation interacting either face-to-face (FtF) or over a computer network. The communication mode had mixed effects on team processes in that members of FtF teams were better informed and made recommendations that were more predictive of the correct team decision, but leaders of CM teams were better able to differentiate staff members on the quality of their decisions. Controlling for the negative impact of FtF communication on staff member differentiation increased the beneficial effect of the FtF mode on overall decision making accuracy. Copyright 1998 Academic Press.

Journal Article↗
PubMed1994

Relative validity of multiple telephone versus face-to-face 24-hour dietary recalls.

The relative validity of multiple telephone 24-hour dietary recalls was evaluated in a feasibility study within the framework of a large prospective investigation on the cause of chronic disease in women. Forty-nine women were interviewed four times both face-to-face and by telephone. Comparison of the total number of calories and intake of protein, carbohydrate, total and saturated fats, cholesterol, fiber, sodium, potassium, calcium, vitamin A, and vitamin C as estimated by multiple face-to-face and telephone interviews revealed an acceptable relative validity for the telephone procedure. Analysis of the position variation in the distribution (percent agreement) comparing the two procedures showed that a change in the distribution of none or one quintile occurs in more than 70% of individuals for all nutrients but vitamin C (69.4%), cholesterol (61.2%), and vitamin A (51.4%). Correlation coefficient analysis showed similar results. Adjustment for nutrient densities did not affect the overall results. Multiple 24-hour telephone dietary recalls appear to be a valid alternative to face-to-face interviews in population studies.

Adult↗
PubMed2006

Amygdala activation during masked presentation of emotional faces predicts conscious detection of threat-related faces.

It has been argued that critical functions of the human amygdala are to modulate the moment-to-moment vigilance level and to enhance the processing and the consolidation of memories of emotionally arousing material. In this functional magnetic resonance study, pictures of human faces bearing fearful, angry, and happy expressions were presented to nine healthy volunteers using a backward masking procedure based on neutral facial expression. Activation of the left and right amygdala in response to the masked fearful faces (compared to neutral faces) was significantly correlated with the number of fearful faces detected. In addition, right but not left amygdala activation in response to the masked angry faces was significantly related to the number of angry faces detected. The present findings underscore the role of the amygdala in the detection and consolidation of memory for marginally perceptible threatening facial expression.

Adult↗
PubMed1998

Telephone vs face-to-face interviews for quantitative food frequency assessment.

OBJECTIVE: To develop and test a quantitative food frequency method for administration by telephone. DESIGN: A comparison study of telephone and face-to-face interviews was conducted among a representative sample of the five major ethnic groups in Oahu, Hawaii. Two interviews were administered 4 to 6 months apart by trained interviewers using identical questionnaires and color photographs of food items showing three different portion sizes. The order of the interviewing methods was randomly assigned. The questionnaire included 115 food items selected to estimate 80% or more of usual dietary intakes. Frequencies and quantities of each item consumed during the past year were obtained. SUBJECTS/SETTING: Subjects were recruited from the Health Surveillance Program of the Hawaii State Department of Health and consisted of 167 men and 158 women, aged 45 to 74 years, who provided a telephone number. Eighty percent of the face-to-face interviews were conducted in the subjects' homes and 20% were conducted at the workplace or the University of Hawaii Cancer Research Center, if requested. STATISTICAL ANALYSES: The paired t test was used to compare the mean daily intakes obtained by the telephone and face-to-face methods. Agreement was measured by the intraclass correlation coefficient (ICC), Pearson correlation coefficient and weighted kappa statistic. RESULTS: The means of energy and each nutrient were slightly higher in the first interview than the second, regardless of the interviewing method. Because of close correspondence among all 3 statistical measures of agreement, only the ICCs are reported. The ICCs ranged from .61 for protein and vitamin A to .69 for dietary cholesterol among men, and from .61 for vitamin C to .74 for saturated fat among women. Agreement was not significantly affected by age, gender, ethnicity, order of interview, or educational level. APPLICATIONS: Telephone interviews to obtain quantitative food frequencies are cost-efficient methods for estimating usual dietary intakes among persons in widely scattered geographic areas. Photographs of the foods in 3 portion sizes mailed in advance help the respondents estimate amounts eaten.

Aged↗
PubMed2002

Telephone vs. face-to-face notification of HIV results in high-risk youth.

PURPOSE: To increase the number of high-risk and homeless youth who receive human immunodeficiency virus (HIV) test results and posttest counseling. METHODS: Oral HIV testing and counseling were offered to high-risk and homeless youth at sites at which youth congregate throughout Portland, Oregon. Subjects were randomized to receive test results and posttest counseling either in a face-to-face manner or with the option of telephone notification. Self-reported demographic and risk-behavior information was collected prior to HIV testing. The differences in the proportion of youth who received their test results were analyzed according to the notification method and demographic characteristics using SPSS. RESULTS: Among the 351 youth who were tested, 48% followed up to receive test results and posttest counseling. Adolescents most likely to receive their results were female, older (19-24 years), and white and those who reported high-risk behaviors. Those given the option of telephone notification were significantly more likely to receive their results than those required to have face-to-face notification (odds ratio = 2.301, 95% confidence interval of 1.499, 3.534). This was true regardless of age, race, history of previous HIV testing, or presence of high-risk behaviors. Two youths tested positive for HIV corroborating previous reports of low HIV prevalence in this population. Both were assigned to the face-to-face notification group and, therefore, no HIV positive results were given by telephone. CONCLUSIONS: The option of telephone notification significantly increased the proportion of youth who received posttest counseling and results following community-based testing.

AIDS Serodiagnosis↗
PubMed2001

Measuring patient satisfaction with anaesthesia: perioperative questionnaire versus standardised face-to-face interview.

BACKGROUND: Patient satisfaction represents an essential part of quality management. Measuring the degree of patient satisfaction can be achieved with a variety of tools such as postoperative visits and patient questionnaires. The primary aim of this study was to quantify the degree of patient satisfaction with anaesthesia. A secondary aim was to compare the questionnaire technique with standardised face-to-face interviewing. METHODS: The authors prospectively studied 700 patients on the second postoperative day. Patients were randomised and allocated to complete either a written questionnaire or to answer the same questions during a standardised face-to-face interview. The questionnaire was subdivided into a set of questions on anaesthesia-related discomfort and another set on satisfaction with anaesthesia care in general. The questions on discomfort were assessed on a 3-point scale, and those on patient satisfaction on a 4-point scale. RESULTS: Response rate was 84% (589 of 700 patients). Internal consistency, as measured by Cronbach's alpha, was 0.84. When evaluating the questions on anaesthesia-related discomfort, the most frequent sensations were "drowsiness" (>75%), "pain at the surgical site" (>55%), and "thirst" (>50%). The data on patient satisfaction showed a high degree of satisfaction (>90%). The responses to questions on anaesthesia-related discomfort revealed only minor differences between the questionnaire and the face-to-face interview. The questions on satisfaction with anaesthesia, however, were answered consistently in a more critical manner during the interview (P<0.0001). CONCLUSIONS: The standardised interview may be more suited to determine patient satisfaction than a questionnaire. Quality improvements are possible for emergence from anaesthesia, postoperative pain therapy, and the treatment of postoperative nausea and vomiting.

Anesthesia↗
PubMed2000

Effects of telephone versus face-to-face interview modes on reports of alcohol consumption.

AIMS AND DESIGN: In order to assess the effects of survey modality on alcohol consumption estimates, data from two surveys using different interview modes (face-to-face and telephone) were compared on several alcohol measures. SETTING AND PARTICIPANTS: Face-to-face survey data were drawn from the 1990 National Alcohol Survey, while the telephone data came from the 1990 Warning Labels Survey. Both surveys used a probability sampling of the US adult general population in the 48 contiguous states. MEASUREMENTS: Measures of alcohol use derived from an identical "graduated frequencies" series included estimates of any drinking in the past 12 months, overall volume, and heavy (5+) drinking days. FINDINGS: Abstention rates did not differ by survey mode, nor did distributions of alcohol consumption by volume and reported frequency of drinking five or more drinks in a day. Multiple regression models including demographic-mode interaction terms were used to examine how mode effects might differ across demographic subgroups. Lower income respondents were under-represented in the telephone sample, and were associated with lower reports of volume and 5+ days, compared to respondents in the face-to-face mode. CONCLUSIONS: The results suggest that although there are few differences in alcohol consumption estimates by interview mode, telephone samples may need to be supplemented or estimates adjusted by income level in order to attain equivalent results.

Alcohol Drinking↗
PubMed1977

Synthesis and characterization of "face-to-face" porphyrins.

The syntheses of four binary porphyrins, two of which are constrained to a "face-to-face" conformation, and their Co2+ and Cu2+ derivatives are described. Electron spin resonance indicates that the intermetallic separation in the binuclear "face-to-face" porphyrins is about 6.5-6.8 A. Electronic spectra and proton magnetic resonance spectra support the postulated "face-to-face" conformations. A hypothesis that related compounds may serve as multielectron redox catalysts for O2 and N2 is presented.

Cobalt↗
PubMed2004

Self-esteem, interpersonal risk, and preference for e-mail to face-to-face communication.

The media choices made by high and low self-esteem Internet users were studied using web-based methodology (n = 265). Participants were asked to rank four media (face-to-face, e-mail, letter, and telephone) in order of preference across four different communication scenarios designed to pose an interpersonal risk. The level of interpersonal risk posed by two of the scenarios (asking for a pay rise and asking for a date) were also experimentally manipulated by randomly allocating participants to a 25%, 50%, or 75% chance of rejection. Low self-esteem users (LSE) showed a significant preference toward e-mail communication compared to high self-esteem users (HSE). This pattern was reversed for face-to-face preferences. Similarly, a greater chance of rejection in a scenario led to e-mail being preferred to face-to-face communication. The results are discussed in light of both the strategic use of different media and the motivated Internet user.

Adult↗
PubMed2004

Comparability of telephone and face-to-face interviews in assessing patients with posttraumatic stress disorder.

INTRODUCTION: Structured clinical interviews are very important in the area of mental health research and services. Prior research comparing the reliability and validity of face-to-face and phone interviews has found high levels of agreement. This project compared the results of face-to-face and phone interviews for two widely used measures: The Clinician-Administered PTSD Scale (CAPS) for assessing posttraumatic stress disorder diagnostic status and symptom severity and the Hamilton Rating Scale for Depression (Ham-D) to determine the severity of major depressive disorder. METHOD: Subjects were 34 veterans recruited from applicants to the PTSD Assessment and Intervention program at the Cincinnati VA Medical Center. Order of interview (in-person or phone) was determined using random assignment within a counterbalanced framework. After attaining satisfactory levels of interrater reliability, four clinicians independently and blindly evaluated the subjects. RESULTS: Pearson correlation coefficients between face-to-face and phone interviews revealed high consistency (CAPS r = 0.745, HAM-D r = 0.748). The level of agreement between the two methods was 82% for the CAPS and 85% for the HAM-D. Diagnostic thresholds for the CAPS and HAM-D, after adjusting for the interview order and time elapsed between interviews, did not differ between the two groups (p = 0.31 for the CAPS and p = 0.96 for the HAM-D). High levels of agreement were achieved between the two methods (kappa = 0.75 for the CAPS using a cutoff of 65 and 0.70 for the HAM-D). The high sensitivity, specificity, and predictive values support the reliability of the phone-interview method. CONCLUSION: Phone interviews are a reliable method of interviewing for use in assessing patients for posttraumatic stress disorder and major depressive disorder.

Aged↗
PubMed1994

Assessing health-related quality of life in elderly outpatients: telephone versus face-to-face administration.

OBJECTIVE: While health-related quality of life (HRQOL) is increasingly being used as an outcome in clinical trials, it is unknown whether HRQOL assessments are influenced by the method of administration. Within the context of a randomized, controlled trial evaluating a pharmacist intervention for elderly outpatients prescribed at least five medications, we compared telephone and face-to-face administration of the SF-36, a widely used HRQOL measure. DESIGN: Survey. SETTING: General Medicine Clinic, Veterans Affairs Medical Center. PATIENTS: At entry, participants in the randomized trial received continuous care from a general medicine clinic physician, were > or = 65 years of age, and were prescribed > or = 5 regularly scheduled medications. Patients were excluded if they were cognitively impaired and had no caregiver available to participate in the study as a proxy or if they resided in a nursing home. MEASUREMENTS: Subjects completed the SF-36 by telephone at closeout and face-to-face at clinic visits within 1 month (mean = 16.7 days). MAIN RESULTS: Telephone administration required significantly less time than face-to-face interviews (10.2 vs 14.0 minutes, P < 0.001). Although systematic differences between modes of administration were generally small, there were substantial nonsystematic discrepancies for all eight SF-36 scales (mean absolute difference scores ranged from 10.8 to 30.1). Discrepancies were greatest for emotional role functioning, physical role functioning, social functioning, and bodily pain; these four scales also demonstrated low to moderate correlations (.33 to .58). CONCLUSIONS: The two modes of administration may not produce interchangeable results. Researchers should be cautious when mixing modes of administration to elderly patients.

Activities of Daily Living↗
PubMed2003

Realtime teleconsultations versus face-to-face consultations in dermatology: immediate and six-month outcome.

We evaluated the outcome of both realtime teleconsultations and face-to-face consultations in dermatology. Forty-six patients were enrolled in an open controlled study. Twenty-nine patients (60%) answered the questionnaire sent to them after six months. Over the six-month follow-up, similar proportions of the two patient groups had visited a general practitioner or a specialist in the consulting hospital. At follow-up, overall patient satisfaction with the consultation, measured on a linear analogue scale (0-10), had fallen only slightly and to the same extent after both types of consultation, that is by 1.2 (SD 3.7) after realtime teleconsultations and by 1.4 (SD 4.5) after face-to-face consultations. The proportions of patients who would prefer the same mode of consultation for their next appointment had decreased from 83% to 50% in the realtime teleconsultation group and from 83% to 62% in the face-to-face consultation group. However, in neither group was the change significant. The study suggests that patient satisfaction with teleconsultation is well preserved after six months.

Adult↗