Intenzitásalapú modellezés és a mértékcsere (Intensity-based modeling and thje change of measure)

A dolgozatban a hitelderivatívák intenzitásalapú modellezésének néhány kérdését vizsgáljuk meg. Megmutatjuk, hogy alkalmas mértékcserével nemcsak a duplán sztochasztikus folyamatok, hanem tetszőleges intenzitással rendelkező pontfolyamat esetén is kiszámolható az összetett kár- és csődfolyamat eloszlásának Laplace-transzformáltja. _____ The paper addresses questions concerning the use of intensity based modeling in the pricing of credit derivatives. As the specification of the distribution of the lossprocess is a non-trivial exercise, the well-know technique for this task utilizes the inversion of the Laplace-transform. A popular choice for the model is the class of doubly stochastic processes given that their Laplace-transforms can be determined easily. Unfortunately these processes lack several key features supported by the empirical observations, e.g. they cannot replicate the self-exciting nature of defaults. The aim of the paper is to show that by using an appropriate change of measure the Laplace-transform can be calculated not only for a doubly stochastic process, but for an arbitrary point process with intensity as well. To support the application of the technique, we investigate the e®ect of the change of measure on the stochastic nature of the underlying process.

Individual decision-making by top executives as a valuable resource for strategic management – A resource-based view and dynamic capability approach

Strategy is highly important for organisational success and the achievement of competitive advantage. Strategy is dynamic and it depends on accurate individual decision-making from medium and high-level managers and executives. Since managers always formulate strategy, its formulation depends mostly on their assertive decisions. Making good decisions is a complex task, even more in today’s business world where a large quantity of information and a dynamic environment forces people to decide without having complete information. As Shafir, Simonson, & Tversky (1993) point out, "the making of decisions, both big and small, is often difficult because of uncertainty and conflict". In this paper the author will explain a basic theoretical framework about top manager's individual decision-making, showing how complex the process of making high-impact decisions is; then, he will compare this theory with one of the most important streams in strategic management, the Resource-Based View (RBV) of the firm. Finally, within the context of individual decision-making and the RBV stream, the author will show how individual decision makers in top management positions constitute a valuable, rare, non-imitable and non-substitutable resource that provides sustained competitive advantage.

The effects of writing process instruction on the writing and reading performance of students with learning disabilities

The purpose of this study was to determine the efficacy of a writing process approach for the instruction of language arts with learning disabled elementary students. A nonequivalent control group design was used. The sample included 24 students with learning disabilities who were in second and third grade. All students were instructed in resource room settings for ninety minutes per day in language arts. The students in the treatment group received instruction using the writing process steps to create complete meaningful compositions on self-chosen topics. A literature-based reading program accompanied instruction in writing to provide examples of good writing and to provide a basis for topic selection. The students in the control group received instruction through the use of the county-adopted textbooks and accompanying worksheets. The teacher followed basic textbook and curriculum guide suggestions which consisted mainly of fill in the blank and matching type exercises. The treatment group consisted of 12 students: five second-graders and seven third-graders. The control group consisted of 12 students: four second-graders and eight third-graders. All students were pretested and posttested using the Woodcock-Johnson Tests of Achievement-Revised (WJ-R ACH) for writing samples and the Woodcock Reading Mastery Test (WRMT) for reading achievement. T-tests were also done to investigate the gain from pre to post for each reading or writing variable for each group separately. The results showed a highly significant difference from pretest to posttest for all writing and reading variables for both groups. Analysis of Covariance showed that the population mean posttest achievement scores for all variables adjusted for the pretest were higher for the treatment group than those for the control group.

Problems faced by beginning principals

The job of a principal is becoming more demanding and more critical each year. Principals are asked to undertake huge challenges and to succeed regardless of what obstacles lie ahead. The purpose of this study was to identify which Administrative Task Areas and Specific Task Areas caused the most difficulties for first- and second-year principals.^ A survey was taken of first- and second-year principals in Dade County, Florida. These beginning principals rated their level of proficiency for each administrative task area and each specific task within those areas. Participants rated their perceptions on a scale from one to four. The data were analyzed based on frequency distributions, percentages, means, and standard deviations.^ Beginning principals perceived themselves as least proficient in the administrative task areas of management and personnel duties. They believed their strongest areas were curriculum and instruction and school-community relations. Within these areas, the specific administrative task areas identified as most problematic were identifying proper procedures for construction in the schools, visiting classrooms to help teachers improve instruction, awareness of issues related to school law, establishing accounting procedures for the school's internal funds, and procedures for dismissing incompetent staff members.^ Many beginning principals surveyed volunteered to make recommendations for future beginning principals. Of these recommendations, the most popular responses addressed obtaining more experience with the budget and internal funds prior to becoming a principal. In addition, there was a strong need for more training dealing with school personnel and the importance of networking with a veteran principal.^ The principal training programs for five of the largest school districts in Florida were reviewed. These programs were found to incorporate a vast amount of the recommendations included in the literature. Florida is moving in the right direction toward excellence in the public schools. ^

An evaluation of English language instruction in universities/colleges in Taiwan

The purpose of this study is about to survey the effectiveness of English teaching in universities/colleges in Taiwan and provide suggestions to the educational authorities for upgrading or improving the English language teaching techniques or methods currently in use. On the one hand, the suggestions of English teachers in universities/colleges are the main concerns in this study. On the other hand, equal attention is given to the opinions and learning attitudes of the students, including the interaction between the teachers and the students.^ A social investigation methodology, consisting of questionnaire and data analysis, is devoted to this evaluation and analysis of teaching effectiveness. Among the significant findings reported in this study is the fact that both students and teachers consider evaluation of teaching effectiveness as a very important aspect of English Language programs at the university/college level. Another significant finding is that students are less concerned about the grades earned or awarded in English Language courses and more concerned about how much they learned in these classes.^ The analysis and suggestions based on the results for English teaching evaluation of universities/colleges in this dissertation can help teachers modify their teaching techniques and methods, the students to adjust their learning attitudes, and the authorities to schematize the English teaching plan that can facilitate the teaching goals to be realized. ^

Intuition as it relates to curriculum, instruction, and resulting academic success in elementary school

Regardless of the fact that children learn in significantly different ways, most curriculum and instruction are guided by the idea that sequential organization of the material to be learned is the best and most efficient way of presenting information to children. Children who learn and think intuitively are denied their preference, forced to conform to the sequential nature of the curriculum and instruction. Based on the theory of psychological type, this study sought to identify any relationship between a student's cognitive style of learning, either Sensing or Intuitive, and his/her academic success in elementary school. The Murphy-Meisgeier Type Indicator for Children was used to identify the cognitive style of students in grades two through eight in a small, private, parochial school. Scores on a standardized achievement test and grades were then analyzed to see if there was a relationship of cognitive style to grades and achievement test scores. Also, the researcher investigated whether or not the teacher's cognitive style had any relationship to students' cognitive style and academic achievement. Although none of the results was statistically significant, the achievement test scores indicated that Sensing students score higher in reading, mathematics concepts, and mathematics computation. However, Intuitive students had higher mean grades in reading and language arts, and virtually equal means mathematics concepts and computation. It was also found that all students, both Sensing and Intuitive, had higher mean grades in the classes of Intuitive teachers. ^

The effect of multimedia instruction on achievement of college history students

The purpose of this study was to investigate the effect of multimedia instruction on achievement of college students in AMR 2010 from exploration and discovery to 1865. A non-equivalent control group design was used. The dependent variable was achievement. The independent variables were learning styles, method of instruction, and visual clarifiers (notes). The study was conducted using two history sections from Palm Beach Community College, in Boca Raton, Florida, between August and December, 1998. Data were obtained by means of placement scores, posttests, the Productivity Environmental Preference Survey (PEPS), and a researcher-developed student survey. Statistical analysis of the data was done using SPSS statistical software. Demographic variables were compared using Chi square. T tests were run on the posttests to determine the equality of variances. The posttest scores of the groups were compared using the analysis of covariance (ANCOVA) at the .05 level of significance. The first hypothesis there is a significant difference in students' learning of U.S. History when students receive multimedia instruction was supported, F (1, 52) = 16.88, p < .0005, and F = (1, 53) = 8.52, p < .005 for Tests 2 and 3, respectively. The second hypothesis there is a significant difference on the effectiveness of multimedia instruction based on students' various learning preferences was not supported. The last hypotheses there is a significant difference on students' learning of U.S. History when students whose first language is other than English and students who need remediation receive visual clarifiers were not supported. Analysis of covariance (ANCOVA) indicated no difference between the groups on Test 1, Test 2, or Test 3: F (1, 45) = .01, p < .940, F (1, 52) = .77, p < .385, and F (1, 53) =.17, p < .678, respectively, for language. Analysis of covariance (ANCOVA) indicated no significant difference on Test 1, Test 2, or Test 3, between the groups on the variable remediation: F (1, 45) = .31, p < .580, F (1, 52) = 1.44, p < .236, and F (1, 53) = .21, p < .645, respectively. ^

Use of conjoint analysis to examine beliefs related to the practice of early literacy instruction

The purpose of the study was to examine the relationship between teacher beliefs and actual classroom practice in early literacy instruction. Conjoint analysis was used to measure teachers' beliefs on four early literacy factors—phonological awareness, print awareness, graphophonic awareness, and structural awareness. A collective case study format was then used to measure the correspondence of teachers' beliefs with their actual classroom practice. ^ Ninety Project READS participants were given twelve cards in an orthogonal experimental design describing students that either met or did not meet criteria on the four early literacy factors. Conjoint measurements of whether the student is an efficient reader were taken. These measurements provided relative importance scores for each respondent. Based on the relative important scores, four teachers were chosen to participate in a collective case study. ^ The conjoint results enabled the clustering of teachers into four distinct groups, each aligned with one of the four early literacy factors. K-means cluster analysis of the relative importance measurements showed commonalities among the ninety respondents' beliefs. The collective case study results were mixed. Implications for researchers and practitioners include the use of conjoint analysis in measuring teacher beliefs on the four early literacy factors. Further, the understanding of teacher preferences on these beliefs may assist in the development of curriculum design and therefore increase educational effectiveness. Finally, comparisons between teachers' beliefs on the four early literacy factors and actual instructional practices may facilitate teacher self-reflection thus encouraging positive teacher change. ^

Capacity-based cost modeling for light rail and bus rapid transit systems

Choosing between Light Rail Transit (LRT) and Bus Rapid Transit (BRT) systems is often controversial and not an easy task for transportation planners who are contemplating the upgrade of their public transportation services. These two transit systems provide comparable services for medium-sized cities from the suburban neighborhood to the Central Business District (CBD) and utilize similar right-of-way (ROW) categories. The research is aimed at developing a method to assist transportation planners and decision makers in determining the most feasible system between LRT and BRT. ^ Cost estimation is a major factor when evaluating a transit system. Typically, LRT is more expensive to build and implement than BRT, but has significantly lower Operating and Maintenance (OM) costs than BRT. This dissertation examines the factors impacting capacity and costs, and develops cost models, which are a capacity-based cost estimate for the LRT and BRT systems. Various ROW categories and alignment configurations of the systems are also considered in the developed cost models. Kikuchi's fleet size model (1985) and cost allocation method are used to develop the cost models to estimate the capacity and costs. ^ The comparison between LRT and BRT are complicated due to many possible transportation planning and operation scenarios. In the end, a user-friendly computer interface integrated with the established capacity-based cost models, the LRT and BRT Cost Estimator (LBCostor), was developed by using Microsoft Visual Basic language to facilitate the process and will guide the users throughout the comparison operations. The cost models and the LBCostor can be used to analyze transit volumes, alignments, ROW configurations, number of stops and stations, headway, size of vehicle, and traffic signal timing at the intersections. The planners can make the necessary changes and adjustments depending on their operating practices. ^

An aspect-oriented approach to designing role-based access control services

Access control (AC) limits access to the resources of a system only to authorized entities. Given that information systems today are increasingly interconnected, AC is extremely important. The implementation of an AC service is a complicated task. Yet the requirements to an AC service vary a lot. Accordingly, the design of an AC service should be flexible and extensible in order to save development effort and time. Unfortunately, with conventional object-oriented techniques, when an extension has not been anticipated at the design time, the modification incurred by the extension is often invasive. Invasive changes destroy design modularity, further deteriorate design extensibility, and even worse, they reduce product reliability. ^ A concern is crosscutting if it spans multiple object-oriented classes. It was identified that invasive changes were due to the crosscutting nature of most unplanned extensions. To overcome this problem, an aspect-oriented design approach for AC services was proposed, as aspect-oriented techniques could effectively encapsulate crosscutting concerns. The proposed approach was applied to develop an AC framework that supported role-based access control model. In the framework, the core role-based access control mechanism is given in an object-oriented design, while each extension is captured as an aspect. The resulting framework is well-modularized, flexible, and most importantly, supports noninvasive adaptation. ^ In addition, a process to formalize the aspect-oriented design was described. The purpose is to provide high assurance for AC services. Object-Z was used to specify the static structure and Predicate/Transition net was used to model the dynamic behavior. Object-Z was extended to facilitate specification in an aspect-oriented style. The process of formal modeling helps designers to enhance their understanding of the design, hence to detect problems. Furthermore, the specification can be mathematically verified. This provides confidence that the design is correct. It was illustrated through an example that the model was ready for formal analysis. ^

A comparison of content-based and context-based teaching on ninth-grade mathematics achievement

The purpose of this study was to determine if an experimental context-based delivery format for mathematics would be more effective than a traditional model for increasing the performance in mathematics of at-risk students in a public high school of choice, as evidenced by significant gains in achievement on the standards-based Mathematics subtest of the FCAT and final academic grades in Algebra I. The guiding rationale for this approach is captured in the Secretary's Commission on Achieving Necessary Skills (SCANS) report of 1992 that resulted in school-to-work initiatives (United States Department of Labor). Also, the charge for educational reform has been codified at the state level as Educational Accountability Act of 1971 (Florida Statutes, 1995) and at the national level as embodied in the No Child Left Behind Act of 2001. A particular focus of educational reform is low performing, at-risk students. ^ This dissertation explored the effects of a context-based curricular reform designed to enhance the content of Algebra I content utilizing a research design consisting of two delivery models: a traditional content-based course; and, a thematically structured, content-based course. In this case, the thematic element was business education as there are many advocates in career education who assert that this format engages students who are often otherwise disinterested in mathematics in a relevant, SCANS skills setting. The subjects in each supplementary course were ninth grade students who were both low performers in eighth grade mathematics and who had not passed the eighth grade administration of the standards-based FCAT Mathematics subtest. The sample size was limited to two groups of 25 students and two teachers. The site for this study was a public charter school. Student-generated performance data were analyzed using descriptive statistics. ^ Results indicated that contrary to the beliefs held by many, contextual presentation of content did not cause significant gains in either academic performance or test performance for those in the experimental treatment group. Further, results indicated that there was no meaningful difference in performance between the two groups. ^

Supplemental instruction, study habits, and the community college student

The purpose of this study was to demonstrate if the academic assistance program Supplemental Instruction (SI) facilitates the acquisition of effective study behaviors through strategies that transcend simple double-exposure to the course material. Its advocates claim it increases academic achievement using learner-centered knowledge and acquisition of effective study behaviors. SI sessions are specifically related to particular courses that students are taking. Sessions are facilitated by the SI leader who has taken the subject matter course in the past. Students review the content of the previous subject matter class using collaborative learning strategies coordinated by a SI leader. In addition, the SI leader models appropriate study behaviors in his or her interactions with the students. ^ An instructor at a large Florida community college who taught five classes of an Anatomy & Physiology I course (traditionally supported by SI) was identified. Two of the classes were randomly selected to participate in SI activities, and two classes were random chosen to participate in alternate, computer-based activities that dealt with the course content, but did not include work in developing students' study behaviors. These treatments were carried out over the course of an entire semester. Participation was mandatory. ^ Data were collected on two variables. Academic achievement in anatomy and physiology content was measured both pre- and post-treatment using an instructor developed examination. Student study behaviors were measured using pre- and post-treatment administration of the Study Behavior Inventory, a valid and reliable instrument that provides scores on three categories of study behaviors: (a) Academic self-efficacy, (b) Preparation for routine academic tasks, and (c) Preparation for long range academic tasks. Measures obtained at the end of the semester of treatment revealed no significant differences between the SI and alternative treatment groups in post-treatment achievement test score and the post-treatment scores on the three study behaviors categories when adjusted for pre-treatment scores. ^ These results suggest that the development of appropriate study behaviors requires more time than SI, as it is now implemented, can provide. In addition, results indicate that improved academic achievement may be attained through any number of means that include repeated exposure to course material. ^

Effect of the Florida A+ Plan on curriculum and instruction in Title I public elementary schools

The purpose of this research was to study the effect of the Florida A+ Plan accountability program on curriculum and instruction in four Title I public elementary schools in the Miami-Dade County Public Schools system. It focused on the experiences of the school principals and the classroom teachers of the four schools as they related to curriculum and instruction. The study included an analysis of the school improvement plans in curriculum and instruction for each school during the school years 1998-2004. ^ The study was conducted in the format of interviews with the school principals and principal selected classroom teachers who taught third, fourth, or fifth grade during the first six years of the Florida A+ Plan. The analysis of the school improvement plans focused on the implementation of curriculum and instruction for each of the four schools. It focused on the goals and measurable objectives selected by each school to improve its instructional program in the academic subjects of reading, mathematics, writing, and science. ^ The findings indicated that under the pressure to improve their school grade on the Florida A+ Plan, each of the target schools, based on individual needs assessments, and restructured their instructional program each school year as documented in their school improvement plans. They altered their programs by analyzing student performance data to realign curriculum and instruction. The analysis of the interviews with the principals and the teachers showed that each school year they restructured their program to align it with the FCAT content. This realigning was a collaborative effort on the part of the administration and the instructional staff. ^

The effects of the use of technology in mathematics instruction on student achievement

The purpose of this study was to examine the effects of the use of technology on students’ mathematics achievement, particularly the Florida Comprehensive Assessment Test (FCAT) mathematics results. Eleven schools within the Miami-Dade County Public School System participated in a pilot program on the use of Geometers Sketchpad (GSP). Three of these schools were randomly selected for this study. Each school sent a teacher to a summer in-service training program on how to use GSP to teach geometry. In each school, the GSP class and a traditional geometry class taught by the same teacher were the study participants. Students’ mathematics FCAT results were examined to determine if the GSP produced any effects. Students’ scores were compared based on assignment to the control or experimental group as well as gender and SES. SES measurements were based on whether students qualified for free lunch. The findings of the study revealed a significant difference in the FCAT mathematics scores of students who were taught geometry using GSP compared to those who used the traditional method. No significant differences existed between the FCAT mathematics scores of the students based on SES. Similarly, no significant differences existed between the FCAT scores based on gender. In conclusion, the use of technology (particularly GSP) is likely to boost students’ FCAT mathematics test scores. The findings also show that the use of GSP may be able to close known gender and SES related achievement gaps. The results of this study promote policy changes in the way geometry is taught to 10th grade students in Florida’s public schools.

A generalized multidimensional index structure for multimedia data to support content-based similarity searches in a collaborative search environment

Since multimedia data, such as images and videos, are way more expressive and informative than ordinary text-based data, people find it more attractive to communicate and express with them. Additionally, with the rising popularity of social networking tools such as Facebook and Twitter, multimedia information retrieval can no longer be considered a solitary task. Rather, people constantly collaborate with one another while searching and retrieving information. But the very cause of the popularity of multimedia data, the huge and different types of information a single data object can carry, makes their management a challenging task. Multimedia data is commonly represented as multidimensional feature vectors and carry high-level semantic information. These two characteristics make them very different from traditional alpha-numeric data. Thus, to try to manage them with frameworks and rationales designed for primitive alpha-numeric data, will be inefficient. An index structure is the backbone of any database management system. It has been seen that index structures present in existing relational database management frameworks cannot handle multimedia data effectively. Thus, in this dissertation, a generalized multidimensional index structure is proposed which accommodates the atypical multidimensional representation and the semantic information carried by different multimedia data seamlessly from within one single framework. Additionally, the dissertation investigates the evolving relationships among multimedia data in a collaborative environment and how such information can help to customize the design of the proposed index structure, when it is used to manage multimedia data in a shared environment. Extensive experiments were conducted to present the usability and better performance of the proposed framework over current state-of-art approaches.