Bolshoi - A Modeling Spreadsheet (Improving Usability of Complex Analytical Modeling Tools)

Spreadsheet programs are very popular financial modeling tools because they allow users to juggle numbers and formulas with a powerful yet intuitive and easy to understand user interface; also, they often are equipped with sophisticated numerical analysis packages for data analysis and powerful presentation utilities for visualizing results. Computer systems performance and reliability modeling tools of today, on the other hand, have un-intuitive user interfaces and are difficult to learn and use. In this work, we propose to design, build, and evaluate Bolshoi, a modeling spreadsheet, with the goal of putting modeling tools comfortably in the hands of non-expert users. In this proposal, we address management of complexity that exists in performance and reliability analysis of real computer and communication systems. Specifically, we propose to do so through the design and development of an advanced modeling tool. Our tool will provide two important functions: (1) a proper interface for building models that will allow system designers not just to define their models, but visualize them in various ways and (2) easy plug-in of existing and future advanced solution techniques. We call this tool Bolshoi, a Modeling Spreadsheet, because it has a spreadsheet-type interface as detailed below. Performance evaluation of real systems is complex, suffers from scalability problems (or the so-called ``state explosion'' problem) and in many cases requires advanced computational techniques. Often, advanced computational techniques are based on exploitation of ``special structure'' in the models (the primary way to deal with state explosion besides getting a bigger machine). With large and complex models, these special structures are very expensive to expose automatically as it involves searching through a combinatorial number of permutations. Proper visualization of models can greatly assist in the discovery of these special structures so that state space reduction techniques can be applied. Discovery of special structure regularly contributes to many orders of magnitude in computational efficiency. Furthermore, models are often defined over infinite state spaces. We believe that a spreadsheet paradigm is ideal for visualizing such models. Without proper modeling tools, much effort and money is wasted by the computer industry, and moreover, the probability of a successful outcome is low. Thus, a good tool is crucial to advances in the state of the art in performance modeling as well as to successful design of systems in the industry. Every system designer should be able to integrate the use of a performance modeling tool into his/her design process. He/she should be able to easily ask ``what-if'' type questions, explore possible design choices, and make decisions based on quantitative results rather than ``gut feeling''. We believe that a modeling spreadsheet is the right abstraction for such tasks, and furthermore, to the best of our knowledge this abstraction has not been exploited for performance evaluation tool purposes. We believe that the approach proposed here will have a significant impact on future performance tool designs as well as make significant strides in wide-spread use of performance evaluation techniques among computer and communication system designers. Furthermore, a modeling tool that does not require expert-level methodology knowledge is also an excellent undergraduate-level and graduate-level educational tool. Opportunities for hands-on experience with modeling and performance evaluation as well as the ability to add new techniques to the tool greatly improve the educational experience of students and their future ability to apply what they have learned in class to design of real computer and communication systems. (Also cross-referenced as UMIACS-TR-2000-10

Accuracy of the Eosinophilic Esophagitis Endoscopic Reference Score in Diagnosis and Determining Response to Treatment

Little is known about the diagnostic utility of the eosinophilic esophagitis (EoE) endoscopic reference score (EREFS), and how scores change in response to treatment. We investigated the operating characteristics of the EREFS in diagnosis of EoE, how the score changes with treatment, and ways to optimize scoring system

Evaluation of Tradeoffs in Resource Management Techniques for Multimedia Storage Servers

Many modern applications can benefit from sharing of resources such as network bandwidth, disk bandwidth, and so on. In addition, many information systems store (or would like to store) data that can be of use to many different classes of applications, e.g., digital libraries type systems. Part of the difficulty in efficient resource management of such systems can then occur when these applications have vastly different performance and quality-of-service (QoS) requirements as well as resource demand characteristics. In this work we present a performance study of a multimedia storage system which serves multiple types of workloads, specifically a mixture of real-time and non-real-time workloads, by allowing sharing of resources among these different workloads while satisfying their performance requirements and QoS constraints. The broad aim of this work is to examine the issues and tradeoffs associated with mixing multiple workloads on the same server to explore the possibility of maintaining reasonable performance and QoS requirements without having to partition the resources. The main contribution of this work is the exposition of the tradeoffs involved in resource management in such systems. Although many different resources can be considered, here we concentrate mostly on the I/O bandwidth resource. The performance metrics of interest are the mean and variance of the response time for the non-real-time applications and the probability of missing a deadline for the real-time applications. The increased use of buffer space resources is also considered as a tradeoff for improvements in the above stated performance metrics, i.e., response time and probability of missing deadlines. (Also cross-referenced as UMIACS-TR-98-30

Potential Added Value of Psychological Capital in Predicting Work Attitudes

Meeting the challenge of effectively managing human resources requires new thinking and approaches. To extend the traditional perspective of economic capital, increasing recognition is being given to human capital and more recently social capital, this article proposes and empirically tests the potential added value that psychological capital may have for employee attitudes of satisfaction and commitment. After first providing the background and theory of PsyCap, this article reports a study of manufacturing employees (N = 74) that found a significant relationship between PsyCap and job satisfaction (r=.373) and organization commitment (r=.313). Importantly, the employees’ PsyCap had a significant added impact over human and social capital on these work attitudes. Future research and practical implications conclude the article

Association Between Body Mass Index and Clinical and Endoscopic Features of Eosinophilic Esophagitis

Because eosinophilic esophagitis (EoE) causes dysphagia, esophageal narrowing, and strictures, it could result in low body mass index (BMI), but there are few data assessing this

Simultaneous identification of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, and Trichomonas vaginalis ‒ multicenter evaluation of the Alinity m STI assay

Abstract Objectives Accurate and rapid diagnosis of sexually transmitted infections (STIs) is essential for timely administration of appropriate treatment and reducing the spread of the disease. We examined the performance of the new Alinity m STI assay, a qualitative real-time multiplex PCR test for simultaneous identification of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), and Trichomonas vaginalis (TV) run on the fully automated Alinity m platform. Methods This international, multicenter study evaluated the accuracy, reproducibility, and clinical performance of the Alinity m STI assay compared to commonly used STI assays in a large series of patient samples encountered in clinical practice. Results The Alinity m STI assay identified accurately and precisely single and mixed pathogens from an analytical panel of specimens. The Alinity m STI assay demonstrated high overall agreement rates with comparator STI assays (99.6% for CT [n=2,127], 99.2% for NG [n=2,160], 97.1% for MG [n=491], and 99.4% for TV [n=313]). Conclusions The newly developed Alinity m STI assay accurately detects the 4 sexually transmitted target pathogens in various collection devices across clinically relevant specimen types, regardless of single or mixed infection status

Nose to Tail: Using the Whole Employment Relationship to Link Worker Participation to Operational Performance

Although many employers continue to adopt various forms of worker participation or employee involvement, expected positive gains often fail to materialize. One explanation for the weak or altogether missing performance effects is that researchers rely on frameworks that focus almost exclusively on contingencies related to the workers themselves or to the set of tasks subject to participatory processes. This study is premised on the notion that a broader examination of the employment relationship within which a worker participation program is embedded reveals a wider array of factors impinging upon its success. I integrate labor relations theory into existing insights from the strategic human resource management literature to advance an alternative framework that additionally accounts for structures and processes above the workplace level — namely, the (potentially implicit) contract linking employees to the organization and the business strategies enacted by the latter. The resulting propositions suggest that the performance-enhancing impact of worker participation hinges on the presence of participatory or participation-supporting structures at all three levels of the employment relationship. I conclude with implications for participation research

The inv dup (15) or idic (15) syndrome (Tetrasomy 15q)

The inv dup(15) or idic(15) syndrome displays distinctive clinical findings represented by early central hypotonia, developmental delay and intellectual disability, epilepsy, and autistic behaviour. Incidence at birth is estimated at 1 in 30,000 with a sex ratio of almost 1:1. Developmental delay and intellectual disability affect all individuals with inv dup(15) and are usually moderate to profound. Expressive language is absent or very poor and often echolalic. Comprehension is very limited and contextual. Intention to communicate is absent or very limited. The distinct behavioral disorder shown by children and adolescents has been widely described as autistic or autistic-like. Epilepsy with a wide variety of seizure types can occur in these individuals, with onset between 6 months and 9 years. Various EEG abnormalities have been described. Muscle hypotonia is observed in almost all individuals, associated, in most of them, with joint hyperextensibility and drooling. Facial dysmorphic features are absent or subtle, and major malformations are rare. Feeding difficulties are reported in the newborn period

Sex Differences in Antiretroviral Therapy Initiation in Pediatric HIV Infection

The incidence and severity of infections in childhood is typically greater in males. The basis for these observed sex differences is not well understood, and potentially may facilitate novel approaches to reducing disease from a range of conditions. We here investigated sex differences in HIV-infected children in relation to antiretroviral therapy (ART) initiation and post-treatment outcome. In a South African cohort of 2,101 HIV-infected children, we observed that absolute CD4+ count and CD4% were significantly higher in ART-naïve female, compared to age-matched male, HIV-infected children. Absolute CD4 count and CD4% were also significantly higher in HIV-uninfected female versus male neonates. We next showed that significantly more male than female children were initiated on ART (47% female); and children not meeting criteria to start ART by >5yrs were more frequently female (59%; p<0.001). Among ART-treated children, immune reconstitution of CD4 T-cells was more rapid and more complete in female children, even after adjustment for pre-ART absolute CD4 count or CD4% (p=0.011, p=0.030, respectively). However, while ART was initiated as a result of meeting CD4 criteria less often in females (45%), ART initiation as a result of clinical disease in children whose CD4 counts were above treatment thresholds occurred more often in females (57%, p<0.001). The main sex difference in morbidity observed in children initiating ART above CD4 thresholds, above that of TB disease, was as a result of wasting and stunting observed in females with above-threshold CD4 counts (p=0.002). These findings suggest the possibility that optimal treatment of HIV-infected children might incorporate differential CD4 treatment thresholds for ART initiation according to sex

Assessing the Effects of Responsible Leadership and Ethical Conflict on Behavioral Intention

[[abstract]]This study develops a research model that elaborates how responsible leadership and ethical conflict influence employees from the perspectives of role theory and attachment theory. Its empirical results reveal that turnover intention indirectly relates to ethical conflict and responsible leadership via the mediating mechanisms of organizational identification and organizational uncertainty. At the same time, helping intention indirectly relates to ethical conflict and responsible leadership only through organizational identification. Finally, the managerial implications for international business and research limitations based on the empirical results are discussed.[[notice]]補正完