Network Kriging

Network service providers and customers are often concerned with aggregate performance measures that span multiple network paths. Unfortunately, forming such network-wide measures can be difficult, due to the issues of scale involved. In particular, the number of paths grows too rapidly with the number of endpoints to make exhaustive measurement practical. As a result, it is of interest to explore the feasibility of methods that dramatically reduce the number of paths measured in such situations while maintaining acceptable accuracy. We cast the problem as one of statistical prediction--in the spirit of the so-called `kriging' problem in spatial statistics--and show that end-to-end network properties may be accurately predicted in many cases using a surprisingly small set of carefully chosen paths. More precisely, we formulate a general framework for the prediction problem, propose a class of linear predictors for standard quantities of interest (e.g., averages, totals, differences) and show that linear algebraic methods of subset selection may be used to effectively choose which paths to measure. We characterize the performance of the resulting methods, both analytically and numerically. The success of our methods derives from the low effective rank of routing matrices as encountered in practice, which appears to be a new observation in its own right with potentially broad implications on network measurement generally.Comment: 16 pages, 9 figures, single-space

Requirements Changes Rework Effects: A Case Study

Although software managers are generally good at estimation, their experience of scheduling reworks is poor. Inconsistent or incorrect effort estimation in turn increases the risk that the completion time for a project will ultimately become problematic. To continually alter software maintenance schedules while maintaining software projects is, in fact, a daunting task. Our proposed framework, validated in a case study, confirms that variables in requirements change suffer from weaknesses in coding, user involvement and user documentation. Our results clearly show that there is significant impact on rework as a result of unexpected errors found to correlate to 1) weak characteristics and attributes as described in the source lines of code, especially in data declaration and data statement, 2) lack of communication between developers and users on a change effect, and 3) unavailability of user documentation. To keep rework under control, new criteria in change request forms are proposed. These criteria are shown in the framework to need refining; thus, the more case studies that are validated, the more reliable the result will be in determining outcomes of effort rework effects

Total Factor Productivity of Philippine Manufacturing Industries

As suggested by vast literature, the Philippine economy has performed poorly over the last three decades due to deterioration in productivity. This paper provides an updated productivity estimates for the manufacturing industries over the period 1956-1992. This paper decomposes this industry productivity growth into technical progress and technical efficiency. It also analyzes the patterns of industry productivity through results of regression method.total factor productivity, manufacturing sector, technical efficiency, output growth

Total Factor Productivity of Philippine Manufacturing Industries

As suggested by vast literature, the Philippine economy has performed poorly over the last three decades due to deterioration in productivity. This paper provides an updated productivity estimates for the manufacturing industries over the period 1956-1992. This paper decomposes this industry productivity growth into technical progress and technical efficiency. It also analyzes the patterns of industry productivity through results of regression method.total factor productivity, manufacturing sector, technical efficiency, output growth

Dysregulated GPCR Signaling and Therapeutic Options in Uveal Melanoma.

Uveal melanoma is the most common primary intraocular malignant tumor in adults and arises from the transformation of melanocytes in the uveal tract. Even after treatment of the primary tumor, up to 50% of patients succumb to metastatic disease. The liver is the predominant organ of metastasis. There is an important need to provide effective treatment options for advanced stage uveal melanoma. To provide the preclinical basis for new treatments, it is important to understand the molecular underpinnings of the disease. Recent genomic studies have shown that mutations within components of G protein-coupled receptor (GPCR) signaling are early events associated with approximately 98% of uveal melanomas

Composition of Rambutan Seeds

The seeds of three rambutan clones (R4, R 7 and R169) were analysed. Proximate analysis of the seeds showed that they contained 11.9-14.1% protein, 37.1-38.9% crude fat (peroleum ether extract), 2.8-6.6% crude fibre and 2.6-2.9% ash on a dry weight basis. The seeds contained 34.1-34.6% moisture. The amino acid profile of the seed protein showed that the protein was of good quality. The major fatty acids in rambutan seed fat were C16:0 (4.36-4.86%); C18:0 (5.93-7.49%); C18:1 (37.91-40.15%); C20:0 (36.14-36.77%) and C20:1 (6.92-7.27%)

The importance of transformational leadership behaviors in team mental model similarity, team efficacy, and intra-team conflict

Using data from 36 combat teams, we examined how transformational leadership is connected with team mental model (TMM) similarity. In addition, we investigated the mediating role of TMM similarity and team efficacy in the link between transformational leadership and intra-team conflict. Data analysis revealed that well-defined transformational leadership behaviors were positively associated with TMM similarity, whereas TMM similarity was positively connected with team efficacy. Results also indicated that higher levels of team efficacy were associated with lower levels of intra-team conflict (task, relationship, and process). In addition, both TMM similarity and team efficacy mediated the link between transformational leadership and intra-team conflict. Implications of findings are discussed

Computation of rotor aerodynamic loads in forward flight using a full-span free wake analysis

The development of an advanced computational analysis of unsteady aerodynamic loads on isolated helicopter rotors in forward flight is described. The primary technical focus of the development was the implementation of a freely distorting filamentary wake model composed of curved vortex elements laid out along contours of constant vortex sheet strength in the wake. This model captures the wake generated by the full span of each rotor blade and makes possible a unified treatment of the shed and trailed vorticity in the wake. This wake model was coupled to a modal analysis of the rotor blade dynamics and a vortex lattice treatment of the aerodynamic loads to produce a comprehensive model for rotor performance and air loads in forward flight dubbed RotorCRAFT (Computation of Rotor Aerodynamics in Forward Flight). The technical background on the major components of this analysis are discussed and the correlation of predictions of performance, trim, and unsteady air loads with experimental data from several representative rotor configurations is examined. The primary conclusions of this study are that the RotorCRAFT analysis correlates well with measured loads on a variety of configurations and that application of the full span free wake model is required to capture several important features of the vibratory loading on rotor blades in forward flight