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This report explains the development of a telephone line multiplexer to be used with a computer based personal paging system. The large geographical area coverage made possible by computer processing results in many calls having to cross telephone tariff boundaries. Since system users cannot be expected to pay long distance charges, dedicated lines which cross tariff boundaries must be leased. Multiplexing applied to those leased lines reduces the cost of data transmission, and is, therefore, justified. The design of the multiplexer proceeds from a specification set which is derived from user response requirements. Fundamentally, the response consists in advising the user, within a reasonable time, that a "page" has been accepted by the system. The specification set is then partitioned into functional blocks which are modeled using flow charts and state diagrams. Logic design follows directly from the models. Production of the multiplexer is followed by field installation. The savings resulting from the multiplexing are considerable.

The purpose of this study was to design a model to evaluate the influence of selected factors on the performance of a telephone delivery system for nutrition information and use the model to evaluate the performance of the Roanoke Dietetic Association Dial-A-Dietitian program. The Dial-A-Dietitian program was established to provide nutrition information to the public by Registered Dietitians. The model entailed a systems approach to evaluate the Roanoke Dietetic Association Dial-A-Dietitian program. The five phases of the model included Enabling Factors (inputs), the Interaction Process, Effort Factors (outputs), Performance (outcome), and Feedback. Feedback entailed the utilization of the results of the evaluation in the decision-making process for future Dial-A-Dietitian programs and their operation. The evaluation instruments, the Encounter Form and the Telephone Survey of clients, included reaction statements and attitude assessment of clients and dietitians. The data were analyzed with frequency distributions. Also the Chi Square Tests of Independence were computed to determine the relationship between the independent variables, Enabling Factors (Phase 1) and Effort Factors (Phase 3), and the dependent variable, Performance (Phase 4). The model was useful in the evaluation of the Dial-A-Dietitian program. The data analysis indicated that the Dial-A-Dietitian program was effective as measured by this model. / Ph. D.

Little research effort has been devoted to human interaction with telephone information systems. This study investigated the effects of system parameters and user characteristics on human behavior in an interactive telephone-based information system. The research method utilized a centraI-composite design to study four variables at five levels each. The four factors manipulated were: synthesized speech rate, time available for user input, subject age, and background music level. Subjects searched a fictitious department store database for 16 specific store items and transcribed 16 information messages which were spoken by a computer speech synthesizer. Subjective ratings of certain features of the system were solicited from the subjects and performance measures were also collected from the subjects on an on-line basis. Performance was evaluated by calculating regression equations relating the dependent measures and the independent variables. A response surface was plotted, and optimal settings for the Information system were also calculated. Two seconds was found to be an optimal time for users to enter their selection. The computer synthesized speech rate should be set close to 120-150 words per minute. Background music or noise level should be kept below 50 dB(A); sound level above 50 dB(A) seriously affected user's ability to understand synthetic speech. Younger subjects (age 14 - 22) performed better in this study than older subjects (age 36- 62). / Master of Science / incomplete_metadata

The user interface for a proposed alternative emergency service was conceived and designed for a standard touch-tone telephone. The service would allow a user to activate an automated, pre-recorded message containing information to aid emergency responders. The user must only press a few specified keys on the telephone key-pad, avoiding the need for verbal interaction with a dispatcher. The interface was designed in terms of providing the necessary instructions for activation and considering various input strategies and feedback. Icons, written instructions, and voice feedback were employed in the development of a successful and effective interface between the user and the system. Because the system is expected to attract elderly users and families with young children, the performance and attitudes of these two age groups in regard to a system prototype were examined to determine if the interface was suitable. A two and eight second initial system response time were imposed upon users to determine any effect these delays might have on user response time, error rate, and subjective attitudes. Additionally, a secondary task, designed to increase cognitive loading was employed to determine if the system is usable while the user is engaged in a dual-task environment. The dependent variables used to gauge the effects of the manipulated variables include the objective measures of user response time and error rate and subjective questionnaire responses. The results of the study indicate that the elderly adults and young children were able to activate the system successfully. System response time and cognitive loading had no significant effect on user performance or subjective attitudes. Distinct practice effects were observed. Attitude scales indicated satisfaction with the service and its interface. Finally, a significant effect of age was observed on average user response time, with the elderly activating the system quicker than the children. / Master of Science

This study examined the effects of five dichotomous variables on human performance using a computer-based telephone information system. The five variables were: speech rate (120 or 240 words per minute), length of input time-out (two or ten seconds), feedback (available or not available), wallet guide - a graphical representation of the information (available or not available), and the database structure (8x2 or 2x6). The research methodology implemented a one-half fraction of a 2⁵ factorial design, requiring only 16 of the 32 possible treatment combinations. Two tasks were included in this study: a search task and a transcription task. The search task consisted of each subject accessing an information system through a touch-tone telephone. The subject listened to the computer as it used synthesized speech to list available menu options. The search task continued until the subject found the target item. The transcription task consisted of listening to and typing an information message for each target item. The experiment ended when 16 target items were found. Four dependent measures were used to evaluate user performance. The search task was evaluated with three measures: user added time (the amount of additional time the subject required to complete the search in excess of the minimum search time imposed by the system design); invalid key presses (the number of times undefined keys on the touch tone telephone were pressed during the search); and user added key presses (the number of additional, valid key presses the subject required to complete the search in excess of the minimum number of key presses required to complete the search). Only one measure was used to evaluate user performance of the transcription task: transcription accuracy score (the number of words that each subject transcribed correctly). The results show four of the five variables (speech rate, database structure, input time-out, and wallet guide) to have a significant effect on human performance. The following interactions were found to have a significant effect on at least one of the dependent measures: database structure by input timeout, database structure by wallet guide, input timeout by wallet guide, and speech rate by wallet guide. Twelve subjective ratings were also analyzed. The results show at least one of the 12 subjective ratings was significantly affected by speech rate, input time-out, or the database structure. Perhaps the most important finding of this research is that complicated auditory information structures can be accessed easily if a wallet guide is provided. In addition to decreasing search time, a wallet guide reduces the number of search errors users make. / Master of Science

This thesis presents enhancements made to software designed for simulating digital mobile radio communication systems. Internally generated two-ray Rayleigh fading channel models as well as imported spatially varying complex channel impulse responses can be utilized in simulations. Implementation of receiver timing jitter and timing recovery models, as well as modifications of the channel generation (two-ray model) and conversion (imported channel), are among the enhancements that have been added. The bit error rate and outage performance of the simulator is compared with analytical results. A study of the impact of the distribution of magnitude and phase components within a channel impulse response is performed. A study utilizing both timing recovery and timing jitter models is also included. It has been found that for site specific BER and outage prediction, more descriptive channel parameters than narrowband fading statistics and statistical moments of a channel's power delay profile are needed. The studies also indicate that for simulations of channels with large delay spread timing recovery is essential. / Master of Science

No / In the present study we report on the effects of mobile phone exposure on short- and long-term memory in male and female subjects. Subjects were university undergraduate students, and consisted of right-handed, males (n = 33) and females (n = 29). Individuals were randomly assigned to one of three experimental conditions: no phone exposure; inactive phone exposure; and active phone exposure. They were provided with a series of words to learn, structured in a two-dimensional shape, and given 3 min to memorise the words. After a 12 min distraction task, they were then asked to draw the shape (spatial) and place the correct words (semantic) into the appropriate boxes. One week later the same subjects were brought back to again redraw the shape and words. Error scores were determined and analysed by non-parametric techniques. The results show that males exposed to an active phone made fewer spatial errors than those exposed to an active phone condition, while females were largely unaffected. These results further indicate that mobile phone exposure has functional consequences for human subjects, and these effects appear to be sex-dependent.

BakgrundTelefonrådgivning är en stor del av hälso- och sjukvården och den expanderar både i Sverige och globalt. Varje år inkommer cirka fyra miljoner samtal till nationella sjukvårdsrådgivningen i Sverige. Telefonsjuksköterskan har en central roll att bedöma patientens symtom och besluta om behov av vård. SyfteSyftet med litteraturöversikten var att beskriva sjuksköterskors upplevelser att arbeta med telefonrådgivning MetodUppsatsen är en strukturerad litteraturöversikt med sammanställning av 16 artiklar med kvalitativ samt kvantitativ ansats. Artiklarna har sökts i två olika databaser CINAHL och PubMed och analyserats med stöd av guiden för generella dataanalys i litteraturöversikter. ResultatFaktorer som sjuksköterskor upplevde underlättade i symtombedömningen via telefon var användning av beslutsstödsystem, bra samarbete med kollegor samt erfarenhetsbaserade strategier. Tidsbristen och en dålig arbetsmiljö försvårade sjuksköterskors symtombedömning samt hinder i beslutsstödsystemen. Sjuksköterskor lyfte behovet av förändrade rutiner och vikten av utbildning som en lösning för hantering av svåra samtal. SlutsatsKommunikationen lyfts som det centrala i telefonrådgivning och det framkommer tydligt att bristande kommunikation ökar risken för missförstånd och därmed hotar patientsäkerheten. Att kommunicera utan visuell kontakt försämrar bedömningsförmågan framförallt i situationer där visuell kontakt är nödvändig. / BackgroundTelephone counseling is a large part of healthcare and it is constantly expanding both in Sweden and globally. Each year, approximately four million calls are received to the Swedish Healthcare Direct. Telephone nurses have a central role to assess the patient's symptoms and decide the need for care. AimThe aim of the literature review was to describe registered nurses' experiences of working with telephone counselling. MethodThe study is a structured literature review with a compilation of 16 articles with both qualitative and quantitative approach. The articles have been searched in two different databases CINAHL and PubMed and analyzed with the support of the guide for general data analysis in literature reviews. ResultsFactors that nurses felt as facilitated symptom assessment via telephone were the use of decision support systems, good collaboration with colleagues and experience-based strategies. The lack of time and a poor work environment made it difficult for nurses to assess symptoms and obstacles in the decision support systems. Nurses highlighted the need for changed routines and the importance of training as a solution for handling difficult conversations. ConclusionsCommunication is highlighted as central to telephone counseling and it is clear that a lack of communication increases the risk of misunderstandings and threatens patient safety. Communicating without visual contact impairs the nurse's assessment skills, especially in certain situations where visual contact is necessary.

published_or_final_version / Business Administration / Master / Master of Business Administration