VTechWorks Repository :: Browsing by Author "Schulman, Robert S."

Browsing by Author "Schulman, Robert S."

Now showing 1 - 20 of 46

Agency theory: a model of investor equilibrium and a test of an agency cost rationale for convertible bond financing
Moore, William T. (Virginia Tech, 1982)
The conflict that may arise among holders of competing claims on firms' assets is being studied under the heading of "agency theory." The primary purposes of the research done in this study were to: (1) economically model the individual investor's consumption-investment decision as it is modified by the agency problem, and (2) to econometrically model the firm's decision to issue convertible versus nonconvertible bonds using explanatory variables which measure the extent of the agency problem. Individual investors are assumed to maximize expected utility of consumption by choosing consumption and investment amounts over a single period. A mathematical model of the investor's consumption-investment decision was derived in an environment characterized by agency problems between stockholders and bondholders. It was demonstrated that if the capital markets exhibit conditions known as spanning and competitivity, then the only investors affected by the agency problem are those holding the affected securities prior to the act of expropriation. It was also shown that the agency problem does not vanish in general, even if investors attempt to avoid the expropriation by holding balanced portions of all outstanding claims on a firm's assets. Implications of the theoretical development were then tested by econometrically modelling the firm's choice of convertible versus nonconvertible debt. The explanatory variables included in the model included measures of the more popular reasons for convertible financing, such as the "debt sweetener" hypothesis and the "delayed equity" rationale discussed in most basic finance textbooks. In addition, measures of agency costs were included, since one possible solution to the agency problem is the issuance of convertible bonds. The empirical results showed that the model accounted for a significant portion of the discrimination between convertible and straight debt, and that the variables designed to measure agency costs were marginally significant.
An Application of Wavelet Techniques to Bi-directionality in the Monte Carlo Ray Trace Environment
Smith, Dwight Eldridge (Virginia Tech, 2002-12-16)
This dissertation presents three different aspects of the incorporation of directionality into the Monte Carlo ray-trace (MCRT) environment: (1) the development of a methodology for using directional surface optical data, (2) the measurement of the bi-directional reflectivity functions for two different surfaces, and (3) MCRT simulations performed using these directional data sets. The methodology presented is based upon a rigorous analytical formulation and is capable of performing simulations of radiation exchange involving directional emission, absorption and reflection given the bi-directional reflectivity functions (BDRF) of the participating surfaces. A wavelet compression technique is presented for the management of extremely large directional data sets. The BDRFs of two different surfaces were acquired using a Surface Optics Corporation model SOC-250 bi-directional reflectometer. These data were processed according to the methodology presented and an MCRT code was used to simulate the action of the SOC-250 in measuring radiant energy reflected from the surfaces of the two samples when illuminated by the source of the SOC-250. Another MCRT code was used to simulate the radiant energy reflected into a plane at the exit of an open-ended rectangular box when the entrance to the box is illuminated by source of the SOC-250. The RMS error between the MCRT simulations of sampling using the SOC-250 and the measured data were determined and then divided by the mean BDRF level of the measured data (RMS/mean[rho]) to provide an estimate of convergence. The RMS/mean[rho] was observed to fall from as much as 138 to 0.84 for the aluminum substrate coated with Krylon Shortcuts Hunter Green Satin aerosol paint as the number of energy bundles emitted in the MCRT simulation went from 103 to 106 at an incident zenith angle of 40 deg. The RMS/mean[rho] was observed to fall from as much as 2.2 to 0.2 for the Norton (150 Fine grit) all-purpose sandpaper coated with Krylon Shortcuts Hunter Green Satin aerosol paint as the number of energy bundles emitted in the MCRT simulation went from 103 to 106 at an incident zenith angle of 40 deg.
Applying software maintenance metrics in the object oriented software development life cylce
Li, Wei (Virginia Tech, 1992-09-05)
Software complexity metrics have been studied in the procedural paradigm as a quantitative means of assessing the software development process as well as the quality of software products. Several studies have validated that various metrics are useful indicators of maintenance effort in the procedural paradigm. However, software complexity metrics have rarely been studied in the object oriented paradigm. Very few complexity metrics have been proposed to measure object oriented systems, and the proposed ones have not been validated. This research concentrates on several object oriented software complexity metrics and the validation of these metrics with maintenance effort in two commercial systems. The results of an empirical study of the maintenance activities in the two commercial systems are also described. A metric instrumentation in an object oriented software development framework is presented.
Calibration Efficacy of Three Logistic Models to the Degrees of Reading Power Test Using Residual Analysis
Granville, Monique V. (Virginia Tech, 1997-11-18)
The publisher of the Degrees of Reading Power test of reading comprehension (DRP) calibrate their test using an item response model called the Rasch or one-parameter logistic model. The relationship between the use of the Rasch model in calibration of the DRP and the use of the DRP as a component of the Virginia Literacy Passport Testing Program (LPT) is addressed. Analyses concentrate on sixth grade students who were administered the DRP in 1991. The question that arises is whether the Rasch model is the appropriate model to use to calibrate the DRP in this high-stakes setting. The majority of research that has been reported by the publisher of the DRP to assess the adequacy of the Rasch model have not included direct checks on model assumptions, model features or model predictions. Instead, they have relied almost exclusively on statistical tests in assessment of model fit. This study will assess the adequacy of fitting DRP test data to the Rasch model through direct examination of the assumptions, features and predictions of the IRT model. This is accomplished by comparing the Rasch model to the less restrictive two- and three-parameter logistic models. Robust IRT-based goodness-of-fit techniques are conducted. When the DRP is used in a high stakes setting, guessing is likely for those in jeopardy of failing. Under these circumstances, we must attend to the possibility that guessing may be a factor and thereby calibrate the DRP with the three-parameter model, as this model takes guessing into account.
Characterization of a Creosote-Contaminated Tie Yard Site and the Effects of Phytoremediation
Fetterolf, Glendon J. IV (Virginia Tech, 1998-06-15)
A creosote treatment facility was active during the 1950’s and 1960’s at a railroad tie yard site. In 1990, creosote contamination was discovered along a creek bank at the site. Phytoremediation was selected as the remedial technology and hybrid poplar trees were planted at the site in 1997. A research project was designed to: 1) characterize the site through collection of soil and ground water samples; 2) assess phytoremediation effects of 3 grasses, clover, fescue and rye, in creosote-contaminated surface soils; 3) perform assessment of the hybrid poplar tree phytoremediation system; 4) develop a hybrid poplar tree evapotranspiration model. This thesis is focused on the first and second items on the research agenda. Soil and ground water samples were collected and analyzed for 6 polycyclic aromatic hydrocarbons (PAHs), acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene and chrysene. Site characterization revealed multiple creosote sources. Areal subsurface bedrock DNAPL distribution, approximately 6500 ft², was much greater than previously reported. Total PAHs (Σ 6 PAHs) in the soil and ground water ranged from below detection limits (BDL) to 8,276 mg/kg and BDL to 1.58 mg/L, respectively. Aqueous phase PAHs should be available for hybrid poplar tree and microbial uptake. Dissolution and diffusion of PAH constituents from the free product phase to the aqueous and soil phases contaminated both matrices. PAH cosolvency effects were also evident. The presence of more soluble PAHs in the aqueous phase enhanced the solubility of two hydrophobic PAHs, chrysene and benzo(b)fluoranthene. Phytoremediation effects of fescue, rye, and clover grasses were assessed in creosote-contaminated surface soils. Over the 9 month period, clover grass growth was very poor. Clover data was not used in comparative analyses. Rye and fescue grasses exhibited acceptable growth. In planted and control (unplanted-amended) plots, acenaphthene, fluorene, phenanthrene, fluoranthene, and pyrene soil concentrations were reduced 72, 50, 73, 55 and 49 percent, respectively. Chrysene reduction was not statistically significant. During the first 4 months of the study, dry site conditions limited grass growth and subsurface biological activity. The site received approximately 16 inches of precipitation during the last 3 months of the study, including multiple, intense precipitation events. The subsurface was saturated for prolonged periods of time and oxygen transfer to indigenous microorganisms was likely limited. The root structures of fescue and rye grasses were neither dense nor complex enough to promote phytoremediation effects. PAH reductions were generally greater for constituents with higher aqueous solubilities. It is thought that PAH losses were primarily due to solubilization and/or microbial uptake.
Clothing behavior, body cathexis, and appearance management of women enrolled in a commercial weight loss program
Robinson, Tammy R. (Virginia Tech, 2003-05-09)
The purpose of this study was to determine the relationship between appearance management, created appearance, body cathexis, and clothing behavior for a group of women enrolled in a commercial weight loss program. Subjects were 171 females enrolled in Weight Watchers® programs in Christiansburg, Virginia. No previous research had investigated clothing behavior, appearance management, created appearance, and body cathexis of women in a weight loss program. Because clothing is such an integral part of the self, it was important to examine the influences and contributions of this variable to weight loss. The proposed research model hypothesized that the following variables would be related: appearance management and created appearance, created appearance and body cathexis, body cathexis and current clothing behavior, and created appearance and current clothing behavior. Other hypotheses tested the relationships between current clothing behavior and prior clothing and between demographics and the following variables: appearance management, created appearance, body cathexis, and current clothing behavior. Results indicated that a greater percentage of weight loss was related to a higher average body cathexis score. Respondents wore clothing that emphasized body parts with which they were more satisfied, and wore clothing that did not emphasize body parts with which they were less satisfied. Results indicated that after weight loss, respondents wore clothing that would emphasize their body with more frequency and also wore clothing that would hide or camouflage their body with less frequency. Current clothing behavior also seemed to be influenced by age and marital status. Findings from the present study provide new information about how women choose clothing based on the level of satisfaction with their bodies and where they have experienced a weight loss. The findings also provide information about the types and styles of clothing that women choose as a result of losing weight. Women in weight loss programs can use clothing to enhance their appearance and improve their body image. By increasing body satisfaction and feeling better about their bodies as they are going through the weight loss program, they may be more likely to continue with their efforts and be more successful in their weight loss.
College-Stress and Symptom-expression in International Students: A comparative study
Shenoy, Uma Ajit (Virginia Tech, 2000-07-05)
The primary purpose of the investigation was to examine differences in symptom-expression between Caucasians and Asians in response to college-stress. College-stress was defined as adjustment problems that students experience as a function of exposure to a college environment. The propensity of each group to express symptoms in response to stress in somatic (i.e., bodily) versus psychological (i.e., anxiety and depression) modes was investigated. Previous reports have postulated a somatization hypothesis for Asians, as opposed to a psychologization tendency in Caucasians. Intra-Asian differences with respect to symptom-expression were also examined. Data were collected electronically. 115 graduate students participated in the study. Using Fisher's transformations to compare correlations, it was found that neither the somatization nor the psychologization hypotheses were supported. However, within Asians depression demonstrated a stronger association with stress than somatic symptoms. A subsidiary purpose of this investigation was to determine whether attribution-style was an aspect of culture that could lead to differences in symptom-expression. It was hypothesized that Asians would have a more external attribution-style, while Caucasian-Americans would have a more internal style. External style was hypothesized to be related to a somatic tendency, while internal style was hypothesized to be related to a psychological tendency. None of these hypotheses were supported. Finally, some exploratory analyses were carried out to assess the effect of demographic variables on symptom-expression. Sex was related to anxiety symptoms, while level of education was related to somatic symptom-reports. Overall, these findings highlight the need for cross-cultural research in psychology to adopt a more systemic approach in studying variables, as opposed to using merely country/culture as an independent variable.
Comparing 12 finite state models of examinee performance on multiple-choice tests
Zin, Than Than (Virginia Tech, 1992)
Finite state test theory models the response behavior of an examinee and establishes the relationship between the ability of the examinee and the observed responses on a multiple-choice test. In finite state modeling, various assumptions about item characteristics and the examinees’ response strategies are made to estimate an examinee ability, and willingness to guess. Twelve sets of plausible assumptions about identifiability of distractors and examinee guessing strategies were adopted and the corresponding finite state models were actualized. Three consequences of the adoption of the 12 sets of assumptions were investigated: 1) the extent to which the resulting ability estimates rank ordered the examinees similarly, 2) variation in the magnitude of ability estimates and the estimated willingness to guess across the 12 models, and 3) the extent to which conclusions about examinees subgroups would differ according to the model employed. Also, conventional number-right scores were compared with the finite state scores with respect to the three outcomes just listed. All scoring methods rank ordered the examinees essentially the same. The magnitude of the finite state scores varied considerably across models mainly due to differing assumptions about the identifiability of distractors. Differing assumptions about examinee guessing strategy had surprisingly little effect on the magnitude of the ability estimates, though estimates of willingness to guess varied consistently according to the assumed strategies. Conclusions about group differences also varied across the models as a result of differing assumptions about both item characteristics and examinee guessing strategies.
A comparison of the effects of conventional testing and two-stage testing procedures on item bias as defined by three statistical techniques
Lane, Carolyn Elizabeth Jones (Virginia Tech, 1978-10-15)
The purpose of the study was to compare the effects on item bias of conventional testing procedures to the effects of two-stage testing procedures. It is conjectured that much of the measurement error identified as bias can be explained by factors, such as guessing or carelessness, attributable to inappropriate matching of test difficulty level and examinee ability level. Methods for detecting bias based on the-traditional definition of item difficulty fail to separate test characteristics from the ability distribution of the respondent sample. The separation of item and ability parameters, however, is an essential ingredient for an objective definition of bias. Such objectivity in measurement is provided by the Rasch latent trait model, which consequently was selected as the basis for this study. Three definitions of bias were considered, two of which were based on the Rasch model. The analyses were conducted using the scores of random subsamples (n=400 each) of black and white students on items selected from three reading subtests. The two-stage testing procedure was simulated using the real data set by "routing" students to one of three difficulty levels of the subtests based on their Rasch ability estimates as determined by a ten item routing test. Results for the two-stage testing procedure were compared with those from the conventional testing procedure at the subtest level. A reduction in the number of items identified as biased under conditions of appropriate matching of examinee ability levels and test difficulty levels was indicated by these analyses. Although the results are not conclusive, it is felt that individualizing according to the examinee's ability level offers promise in the direction of reading differential cultural measurement error.
Development and Evaluation of a Model of Behavioral Representation Techniques
Chase, Joseph D.; Schulman, Robert S.; Hartson, H. Rex; Hix, Deborah (Department of Computer Science, Virginia Polytechnic Institute & State University, 1993)
A user-centered approach to interactive system development requires a way to represent the behavior of a user interacting with an interface. While a number of behavioral representation techniques exist, not all provide the capabilities necessary to support the interaction development process. Based on observations of existing representation techniques and comments from users of the User Action Notation (UAN), a user- and task-centered behavioral representation technique, we have developed a model of behavioral representation techniques. Our model is an epistemological framework for discussing, analyzing, extending, and comparing existing behavioral representation techniques, as well as being a springboard for developing and evaluating new techniques. We present the model and results of our evaluation demonstrating the model's reusability and utility within the context of behavioral representation techniques.
Development and Testing of an Evaluation Procedure for User InterfaceManagement (UIMS)
Hix, Deborah; Tan, Kay C.; Schulman, Robert S. (Department of Computer Science, Virginia Polytechnic Institute & State University, 1989)
A user interface management system or UIMS is an interactive system for supporting the design, production, and execution of human-computer interfaces. This paper reports on the development and empirical testing of an evaluation procedure to produce quantifiable criteria for evaluating and comparing UIMS. The form-based evaluation procedure results in quantitative ratings along two dimensions: functionality and usability. Specification/implementation techniques used by a UIMS are also quantitatively rated. An empirical study has indicated that the procedure produces reliable, useful results.
Disconnected: An Examination of Organizational Trust and Psychological Sense of Community in a Networked Environment
Franklin, Kellee Michelle (Virginia Tech, 2004-03-31)
The concept of trust in human relationship has gained much attention over the past decade. The majority of the trust literature focuses on the definition of trust and the development and maintenance of trust. Most scholars agree that trust is developed and maintained through dialogue and socialization, including verbal and nonverbal social cues. The literature suggests that individuals share information and build communities with persons they trust. Within an organizational environment, higher degrees of trust enhance the discovering processes and, ultimately, the ability of groups and organizations to fully function. A "sense of community" is created in environments that encourage open and honest communication among their members. Despite the research supporting a link between socialization, communication, and trust, there is almost no research that specifically addresses the relationship between communication technologies that eliminate face-to-face interaction and organizational trust and sense of community. E-mail, a tool that enables members of an organization to communicate with one another despite differences in time and location, is used by a vast majority of corporations to communicate with its organizational members. While e-mail communication provides many advantages, the literature in this area suggests that this tool may limit the amount of "human moments" at work, which may relate to decreased levels of trust and feelings of community in the workplace. This study was aimed at learning more about this phenomenon. Using a questionnaire developed that included three valid and reliable instruments of trust and sense of community, responses were collected from members of selected teams within a large, international organization to examine the relationships between trust, community, and e-mail communication. Other demographic and organizational data was also collected. Although no relationship was found between e-mail use, organizational trust, and psychological sense of community in the workplace, the results suggest that factors other than communication medium influence feelings of trust and community. Implications of the findings as well as recommendations for practice and future research are provided.
Effect of Carbohydrate-Protein Beverage on Glycogen Resynthesis and Muscle Damage Induced By Eccentric Resistance Exercise
Wojcik, Janet Regina (Virginia Tech, 1998-04-17)
This study examined effects of carbohydrate (C), carbohydrate-protein (CP), or placebo (P) beverages following eccentric resistance exercise on muscle damage by serum creatine kinase (CK), muscle protein breakdown by urinary 3-methylhistidine (3MH), muscle soreness, isokinetic muscle strength, muscle glycogen resynthesis, and serum hormones. Untrained males (N=26) underwent a 9-day controlled meat-free diet and 24 hr urine collections. To reduce glycogen, subjects cycled for 40 min at 70% of VO_2peakfollowed by 5 cycling sprints on day 4 evening. On day 5, fasted subjects performed 100 eccentric leg flexions at 120% of 1-RM and drank C (n=8, 1.25 g C/kg), CP (n=9, 0.875 g C/kg, 0.375 g protein/kg), or P (n=9) beverages immediate post-exercise (IPE) and 2 hr later. Muscle biopsies were taken IPE on day 5, and days 6 and 8 mornings. Blood was obtained days 4-10 fasted plus IPE, 3 hr, and 6 hr post-exercise on day 5. At 3 hr on day 5, insulin was higher for CP (24.6 ( 15.5 µIU/ml) and C (17.2 +/- 10.9 µIU/ml) than P (5.3 +/- 0.4 µIU/ml, p<.05). Glycogen was low on day 5, partially recovered on day 6, and normal by day 8 (p<.01) with no difference among groups. Isokinetic quadriceps peak torque at 60^o/s decreased 24% on day 6 and remained depressed by 21% on d 8 (p<.01) for all groups. Soreness peaked on day 7 and CK on day 8 (p<.01) with no differences by group. CK increased (p<.01) over day 5 (delta CP 24.6 +/- 19.1, delta P 39.2 +/- 71.6, delta C 70.8 +/- 60.4 U/L) and was highest for C (p<.05). On day 5, CP had lowest 3MH (193.0 +/- 13.8 µmol/d) versus C (251.1 +/- 22.5 µmol/d, p<.05). Testosterone at 3 hr on day 5 was lower for C (4.2 +/- 0.3 ng/ml) and CP (4.3 +/- 0.3 ng/ml) versus P (5.1 +/- 0.2 ng/ml, p<.05). In summary, glycogen, muscle strength and soreness were unaffected by beverage. However, a CP beverage may be beneficial for reducing muscle damage and protein breakdown on the day of eccentric resistance exercise.
Effects of clothing conformity on preschool children's social interactions
Spencer, Marilyn Sanderson (Virginia Tech, 1976-11-15)
The purpose of this study was to explore the effects of clothing conformity on the social interaction of two groups of preschool children of two socio-economic classes. Subjects were six randomly selected children from a group of fifteen nursery school children, representing the middle economic class and six children from a group of thirteen Head Start children designated as lower economic class. The subjects were observed for 45 minutes while engaged in free play periods. Three separate observation series were conducted while the subjects were wearing their own play clothes, experimental garments, and when again dressed in their own play clothing. Statistical analysis of the number of verbalizations initiated by subjects to themselves and to others indicated that clothing conformity did not appear to affect preschool children's social interactions. There were no lasting interactional trends, and experimental clothing did not affect the social interaction of children of middle and lower economic backgrounds. Anecdotal records revealed that the lower-class children had considerable interest in and awareness of clothing. This was in contrast to an extreme lack of interest exhibited by the middle-class children.
Effects of uniform guidelines on employee selection procedures in college placement offices
McBride, James L. (Virginia Polytechnic Institute and State University, 1982)
Beginning with the Civil Rights Act of 1964, Congress and the courts have legislated and adjudicated laws in an effort to eliminate discrimination in employment opportunities on the grounds of race, color, sex, religion, or national origin. In 1978, the Uniform Guidelines on Employee Selection Procedures were jointly issued by several federal administrative agencies and have included within their framework the types of employment selection practices operating in many contemporary college and university placement offices. These regulations have serious implications for college placement offices in which interview selection and referral practices fail to assist all students in fair and equitable ways. This study investigated from two perspectives the problems for college placement personnel that are associated with these guidelines. First, legal research methodology was implemented to trace the historical and topical development of relevant legislative and case law. The findings of the legal research indicated that the federal government and the courts had mandated, rather consistently, two controlling standards that pertain to individual and class civil rights. Those standards are equality and neutrality. Failure of an entity to comply with either of these standards, except in listed instances, had been judged discriminatory under civil rights law. Based on existing litigations, judgments against college placement offices could be proscriptive, corrective, and/or compensatory in effect. Furthermore, there exists the potential for loss of governmental funding, the extent of which remains undetermined. Secondly, the findings of the survey research indicated that a majority of college placement offices sampled (60.9%) were operating student interview selection and referral systems within the compliance standards of the Uniform Guidelines. Almost categorically, placement officers supported student interview systems that were void of prohibitive selection criteria (sex, race, color, or national origin). On the other hand, the Uniform officers void of religion, placement officers indicated more discriminatory trends where neutral selection criteria (academic majors, grade point averages, or degree levels) were concerned. Additionally 25.93 of the respondent institutions indicated that they had either changed, or were planning to change their interview selection procedures to be more in compliance with the law. The survey research also led to significant findings among several demographic characteristics related to college placement offices, their personnel, and the Uniform Guidelines. Those characteristics included: college placement officers’ familiarity with and primary sources of information about the regulations; certain perceived resource needs; the adequacy of placement office staffing; and, governmental auditing of interview selection and referral procedures. In combination these research findings indicated several factors which college placement personnel need to be aware of in order to bring their operations into legal compliance.
An empirical investigation of the cash flow predictability of historical cost, general price level, and replacement cost income models
White, G. Thomas (Virginia Polytechnic Institute and State University, 1983)
One of the fundamental premises of financial reporting by business enterprises is that it should provide users with information that will assist them in predicting the amounts, timing and uncertainty of future cash flows of the enterprise. The requirement for alternative income measurements was partially justified by an assumed correspondence between the new information and the cash flow prediction objective. The existence of that correspondence, however, has not been precisely verified by the research to date. The overall objective of this research was to contribute additional evidence to address conflicts in the prior research findings, and additionally, to consider possible industry and firm-size effects on the ability to predict cash flow from alternative incomes. A data base was compiled from COMPUSTAT tapes (historical cost), the Parker model restatement procedures (general price-level) and the Easman data base that used the Falkenstein-Weil restatement model (replacement cost). One conclusion was that the alternative income measurements produce different cash flow forecast errors. Overall, historical cost net income produced the lowest forecast errors for two approximations of cash flow. The inclusion of monetary gains/losses and holding gains/losses in net income did not improve predictions, and in one case worsened them. Another conclusion was that a multiple linear regression model produced significantly lower forecast errors for both cash flow definitions. The simple linear and exponential regression prediction models did not produce different forecast errors. Finally, both an industry effect and a firm-size effect were identified in the prediction of working capital from operations. When net income plus depreciation was the object of prediction, an industry effect was identified but not a firm-size effect. The overall impact of these findings is that the alternative income measurements should be justified on some basis other than facilitating cash flow prediction. In fact, a random-walk cash flow prediction model performed better than any prediction based on net income. Financial accounting standards in the area of alternative income measurements should consider possible industry and firm-size differences. The choice of cash flow definition is apparently critical because different conclusions were obtained.
An empirical study of software reuse: the impact of the object-oriented paradigm and human factors
Lewis, John A. (Virginia Tech, 1991-04-05)
Little or no empirical validation exists for many of software engineering's basic assumptions. While some of these assumptions are intuitive, the need for scientific experimentation remains clear. Several assumptions are made about the factors affecting software reuse. In particular, the object-oriented paradigm and various human factors are hypothesized to affect the successful reuse of software components. This dissertation describes a controlled experiment designed to evaluate the impact of the object-oriented paradigm and human factors on software reuse. The human factors under investigation include managerial influence and cognitive abilities. This experiment concludes (a) the object-oriented paradigm makes significant contributions to productivity, (b) language differences are far more important when programmers reuse than when they do not, and (c) the object-oriented paradigm holds a particular affinity to the reuse process, (d) reuse results in higher productivity than no reuse independent of language paradigm, (e) the level of management encouragement does affect the reuse process, and (f) the cognitive ability of visualization does relate to effective reuse.
An Empirical Study of the Effects of Context-Switch, Object Distance, and Focus Depth on Human Performance in Augmented Reality
Gupta, Divya (Virginia Tech, 2004-06-09)
Augmented reality provides its user with additional information not available through the natural real-world environment. This additional information displayed to the user potentially poses a risk of perceptual and cognitive load and vision-based difficulties. The presence of real-world objects together with virtual augmenting information requires the user to repeatedly switch eye focus between the two in order to extract information from both environments. Switching eye focus may result in additional time on user tasks and lower task accuracy. Thus, one of the goals of this research was to understand the impact of switching eye focus between real-world and virtual information on user task performance. Secondly, focus depth, which is an important parameter and a depth cue, may affect the user's view of the augmented world. If focus depth is not adjusted properly, it may result in vision-based difficulties and reduce speed, accuracy, and comfort while using an augmented reality display. Thus, the second goal of this thesis was to study the effect of focus depth on task performance in augmented reality systems. In augmented reality environments, real-world and virtual information are found at different distances from the user. To focus at different depths, the user's eye needs to accommodate and converge, which may strain the eye and degrade performance on tasks. However, no research in augmented reality has explored this issue. Hence, the third goal of this thesis was to determine if distance of virtual information from the user impacts task performance. To accomplish these goals, a 3x3x3 within subjects design was used. The experimental task for the study required the user to repeatedly switch eye focus between the virtual text and real-world text. A monocular see-through head- mounted display was used for this research. Results of this study revealed that switching between real-world and virtual information in augmented reality is extremely difficult when information is displayed at optical infinity. Virtual information displayed at optical infinity may be unsuitable for tasks of the nature used in this research. There was no impact of focus depth on user task performance and hence it is preliminarily recommended that manufacturers of head-mounted displays may only need to make fixed focus depth displays; this clearly merits additional intensive research. Further, user task performance was better when focus depth, virtual information, and real-world information were all at the same distance from the user as compared to conditions when they were mismatched. Based on this result we recommend presenting virtual information at the same distance as real-world information of interest.
An empirical study of the fidelity of organziational accounting communication and the impact of organizational culture
Johnson, Steven D. (Virginia Tech, 1991-06-04)
Communication and culture both play essential roles in organizations. The effective communication of accounting information is required to coordinate business operations and move the organization toward the accomplishment strategic goals. Without effective communication, the most sophisticated analyses and crucial reports will fail to generate appropriate decisions and actions. Culture is a symbolic system of values that helps the members of an organization explain, coordinate, and evaluate behavior and to ascribe common meanings to events and symbols encountered in the organization. Organizations confine the experience and interaction of its members into structured and recurring patterns. As organization members interact, shared meaning for issues of common interest evolve. A technical organizational language develops whose symbols have definite and common meaning. If the culture of organizations or subcultures within an organization are different, dissimilar meanings could be ascribed to the management accounting terms (symbols) used to communicate accounting information. Dissimilar meanings could inhibit the fidelity of accounting communication within and between organizations and organization subunits.
An Empirical Study of the Object-Oriented Paradigm and Software Reuse
Lewis, John A.; Henry, Sallie M.; Kafura, Dennis G.; Schulman, Robert S. (Department of Computer Science, Virginia Polytechnic Institute & State University, 1992)
This paper describes the preliminary results of a controlled experiment designed to evaluate the impact of the object-oriented paradigm on software reuse. The experiment concludes that (1) the object-oriented paradigm substantially improves productivity, although a significant part of this improvement is due to the effect of reuse, (2) reuse without regard to language paradigm improves productivity, (3) language differences are far more important when programmers reuse than when they do not, and (4) the object-oriented paradigm has a particular affinity to the reuse process.

Browsing by Author "Schulman, Robert S."

Results Per Page

Sort Options