A layout algorithm for hierarchical graphs with constraints

A new method is developed for reducing edge crossings in the layout of directed graphs for display. The method will reduce edge crossings in graphs which have constraints on the location or movement of some of the nodes. This has not been available in previously published methods. An analysis of the strategies used to choose rank pairs for edge crossing reduction shows that this choice will dramatically affect the amount of crossings eliminated. This method is directly applicable to the reduction of edge crossings in the general graph

An Evidence-Based Determination of Whether Effective Leadership Competencies are Universal and Transferable.

Poor executive leadership of organizations over the last 20 years has resulted in the destruction of stakeholder value, loss of jobs, and in some cases, risk to the entire enterprise. An executive search firm database, encompassing 16,000 leaders from 300 organizations, was analyzed to determine if the commonality and transferability of leadership competences could be used to improve executive assessment. Implicit leadership theory, where leaders are gauged by the individuals that surround them, served as the theoretical foundation. The study also relies on a leadership competency model used by the executive search firm that constructed the database and is based primarily on behavioral-event interviewing method of assessment. Inferential statistics were used to analysis the data with analysis of variance and Tukey post-hoc methods for testing mean differences, and with correlation and regression analysis to test for associations and explained variances. The executive roles were found to show a commonality of competency profiles and transferability across the disciplines studied, with the exception of the chief executive officer (CEO) role. These findings suggest that a new CEO should not be sourced directly from the other executive functions inside or outside the firm. The Outstanding leader database indicates a strong universality and interchangeability of leaders at this higher-ranking level, regardless of discipline and industry; the database is a source of new potential CEOs. Results Orientation is by far the strongest developed of the competencies for all leaders. Social change will result from better selection of top executive leaders with a positive impact for employees and all the stakeholders of the corporation or institution

To haft and to hold: Evidence for the hafting of Clovis fluted points

Clovis fluted points vary considerably in technology and morphology, but also share a set of attributes, the most diagnostic of which are the flute scars, the remnants of the flake removals from the basal region that travelled up towards the tip. Fluting on Clovis and Clovis-like points generally extends no further than a third of the way up the face of the point. Finished points are usually ground smooth along the base and lower edges, suggesting facilitation of the hafting (attachment) to a wooden shaft or handle by way of an ivory or bone socket. The points may have been hafted directly to a main-shaft and used as a thrusting spear during close encounter attacks, or in the hand as knife or butchery tool. Alternatively, an intermediary shaft, or foreshaft may have been used to secure the point. The suggestion of foreshafts being used by Clovis hunters received support after the discovery of bone rods in association with mammoth remains and Clovis points at the type site at Blackwater Draw, New Mexico in 1936. Several other Clovis-aged sites across North America have yielded ivory and beveled rods that have also been associated with foreshafts and the hafting of Clovis points. Scratches that are present on a couple of Clovis points made on varieties of obsidian, have been identified as being “hafting abrasion” evidence, this roughening of the surface would have helped in securing the point into the shaft or socket. In one example from the Hoyt site in Oregon, remains of a “pitch” or hafting adhesive was discovered in the abrasions in the fluted area of the point

Extending UTAUT2 To Explore Consumer Adoption Of Mobile Payments

There is a growing interest in studying the adoption of m-payments but literature on the subject is still in its infancy and no empirical research relating to this has been conducted in the context of the UK to date. The aim of this study is to unveil the current situation in m-payment adoption research and provide future research direction through the development of a research model for the examination of factors affecting m-payment adoption in the UK context. Following an extensive search of the literature, this study finds that 179 relationships between independent and dependent variables have been analysed by 30 existing empirical m-payment and m-banking adoption studies. From analysis of these relationships the most significant factors found to influence adoption are uncovered and an extension of UTAUT2 with the addition of perceived risk and trust is proposed to increase the applicability of UTAUT2 to the m-payment use context

The Generalization of a Decision Simulation

This paper discusses a research project in which an artificial intelligence decision making model in the domain of politics is applied to business decisions in general and an information technology decisions in particular. We describe the original VOTE program, which simulated Congressional roll call voting. Then we discuss extensions to VOTE motivated by its application to business domains. The primary sample decision problem is the purchase of a personal computer. The VOTE program is not a prescriptive model ofdecision making, but rather an attempt to create a realistic simulation of human cognitive behavior

QUALITATIVE DECISION EXPLANATION FOR INFORMATION TECHNOLOGY INVESTMENT

Many business decisions involve issues that are not amenable to quantitative measures and analysis. One such domain of decisions is large-scale investments in information technology. Traditional capital budgeting methods have not proven effective. In this paper, we present an alternative paradigm for qualitative decision analysis, embodied in the artificial intelligence program: VOTE. We describe the technology investment domain in general, and how VOTE models goals and agents in this domain. We apply the VOTE model to a specific decision taken from a. study of a major information technology investment decision.Information Systems Working Papers Serie

Potential outcome simulation for efficient head-to-head comparison of adaptive dose-finding designs

Dose-finding trials are a key component of the drug development process and rely on a statistical design to help inform dosing decisions. Triallists wishing to choose a design require knowledge of operating characteristics of competing methods. This is often assessed using a large-scale simulation study with multiple designs and configurations investigated, which can be time-consuming and therefore limits the scope of the simulation. We introduce a new approach to the design of simulation studies of dose-finding trials. The approach simulates all potential outcomes that individuals could experience at each dose level in the trial. Datasets are simulated in advance and then the same datasets are applied to each of the competing methods to enable a more efficient head-to-head comparison. In two case-studies we show sizeable reductions in Monte Carlo error for comparing a performance metric between two competing designs. Efficiency gains depend on the similarity of the designs. Comparing two Phase I/II design variants, with high correlation of recommending the same optimal biologic dose, we show that the new approach requires a simulation study that is approximately 30 times smaller than the conventional approach. Furthermore, advance-simulated trial datasets can be reused to assess the performance of designs across multiple configurations. We recommend researchers consider this more efficient simulation approach in their dose-finding studies and we have updated the R package escalation to help facilitate implementation.Comment: 27 pages, 4 figures, 1 tabl

Synthetic studies on silyl glyoximines, alternaric acid, and quaternary donor site cyclopropanes

Silyl glyoxylates were converted to a variety of nitrogenous derivatives and their suitability for three component coupling reactions was investigated. Silyl glyoximines bearing electron-rich or -neutral N-aryl groups were suitable electrophiles for addition of sp3-hybridized alkyllithium nucleophiles. The relatively unstudied [1,2]-aza-Brook rearrangement serves as a key mechanistic feature for the generation of a glycinate enolate for second-stage electrophilic trapping, which could be accomplished with aldehyde, cyanoformate, or anhydride electrophiles. These reactions thus demonstrate the ability of silyl glyoximines to serve as dipolar glycinate linchpins complementary to their silyl glyoxylate parents. To the best of our knowledge, the use of an aza-Brook rearrangement to enable multicomponent coupling is without precedent. The ability of silyl glyoxylates to serve as effective linchpins for the union of nucleophiles and electrophiles at a glycolic acid junction has been leveraged in synthetic efforts toward the total synthesis of alternaric acid, a biologically active natural product. The second-stage glycolate aldol reaction with the aldehyde that directly affords the aldol subunit in the natural product suffers from poor diastereoselectivity. Efforts to overcome this obstacle demonstrated that a wide variety of substituents are tolerated on the aldehyde electrophile, and exert varying degrees of stereochemical control. Significantly, a method for generating functionalized vinyl nucleophiles suitable for efficient three component coupling reactions has been established, increasing the convergency of the route and expanding known reactivity patterns of silyl glyoxylates. A diastereoselective synthesis of pentasubstituted tetrahydrofurans via a Lewis acid catalyzed (3 + 2)-annulation of quaternary donor site cyclopropanes and aldehydes is described. Yields (up to 95%) and diastereoselectivities (up to 99:1) are in some cases competitive with related (3 + 2)-annulation reactions of tertiary donor site cyclopropanes, despite the increased hindrance and reduced steric differentiation between the substituents on the donor site. Chirality transfer studies are consistent with the operation of a similar mechanism for both quaternary and tertiary donor site cyclopropanes, and demonstrate the impact of the stability of carbenium ion character at the cyclopropane donor site on the reaction course. Significantly, it is still possible to obtain highly enantioenriched tetrahydrofuran products from enantioenriched cyclopropane starting materials