Comprehension of object-oriented software cohesion: The empirical quagmire

Chidamber and Kemerer (1991) proposed an object-oriented (OO) metric suite which included the Lack of Cohesion Of Methods (LCOM) metric. Despite considerable effort both theoretically and empirically since then, the software engineering community is still no nearer finding a generally accepted definition or measure of OO cohesion. Yet, achieving highly cohesive software is a cornerstone of software comprehension and hence, maintainability. In this paper, we suggest a number of suppositions as to why a definition has eluded (and we feel will continue to elude) us. We support these suppositions with empirical evidence from three large C++ systems and a cohesion metric based on the parameters of the class methods; we also draw from other related work. Two major conclusions emerge from the study. Firstly, any sensible cohesion metric does at least provide insight into the features of the systems being analysed. Secondly however, and less reassuringly, the deeper the investigative search for a definitive measure of cohesion, the more problematic its understanding becomes; this casts serious doubt on the use of cohesion as a meaningful feature of object-orientation and its viability as a tool for software comprehension

Application of the NASA airborne oceanographic lidar to the mapping of chlorophyll and other organic pigments

Laser fluorosensing techniques used for the airborne measurement of chlorophyll a and other naturally occurring waterborne pigments are reviewed. Previous experiments demonstrating the utility of the airborne oceanographic lidar (AOL) for assessment of various marine parameters are briefly discussed. The configuration of the AOL during the NOAA/NASA Superflux experiments is described. The participation of the AOL in these experiments is presented and the preliminary results are discussed. The importance of multispectral receiving capability in a laser fluorosensing system for providing reproducible measurements over wide areas having spatial variations in water column transmittance properties is addressed. This capability minimizes the number of truthing points required and is usable even in shallow estuarine areas where resuspension of bottom sediment is common. Finally, problems encountered on the Superflux missions and the resulting limitations on the AOL data sets are addressed and feasible solutions to these problems are provided

The Use of Quantitative and Qualitative Analysis in the General Chemistry Laboratory

Author Institution: California Institute of Technology, Pasadena, Californi

Fourteen Years of Education and Public Outreach for the Swift Gamma-ray Burst Explorer Mission

The Sonoma State University (SSU) Education and Public Outreach (E/PO) group leads the Swift Education and Public Outreach program. For Swift, we have previously implemented broad efforts that have contributed to NASA's Science Mission Directorate E/PO portfolio across many outcome areas. Our current focus is on highly-leveraged and demonstrably successful activities, including the wide-reaching Astrophysics Educator Ambassador program, and our popular websites: Epo's Chronicles and the Gamma-ray Burst (GRB) Skymap. We also make major contributions working collaboratively through the Astrophysics Science Education and Public Outreach Forum (SEPOF) on activities such as the on-line educator professional development course NASA's Multiwavelength Universe. Past activities have included the development of many successful education units including the GEMS Invisible Universe guide, the Gamma-ray Burst Educator's guide, and the Newton's Laws Poster set; informal activities including support for the International Year of Astronomy, the development of a toolkit about supernovae for the amateur astronomers in the Night Sky Network, and the Swift paper instrument and glider models.Comment: 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013: paper 42 in eConf Proceedings C130414

Object-oriented cohesion as a surrogate of software comprehension: An empirical study

The concept of software cohesion in both the procedural and object-oriented paradigm is well known and documented. What is not so well known or documented is the perception of what empirically constitutes a cohesive 'unit' by software engineers. In this paper, we describe an empirical investigation using object-oriented (OO) classes as a basis. Twenty-four subjects (drawn from IT experienced and IT inexperienced groups) were asked to rate ten classes sampled from two industrial systems in terms of their overall cohesiveness; a class environment was used to carry out the study. Four key results were observed. Firstly, class size (when expressed in terms of number of methods) did not tend to influence the perception of cohesion by any subjects. Secondly, well-commented classes were rated most highly amongst both IT experienced and inexperienced subjects. Thirdly, the empirical study suggests that cohesion comprises a combination of various class factors including low coupling, small numbers of attributes and well-commented methods, rather than any single, individual class feature per se. Finally, the research supports the view that cohesion is a subjective concept reflecting a cognitive combination of class features; as such it is a surrogate for class comprehension

La confianza organizacional como variable mediadora entre el capital psicológico y la conducta de compartir conocimiento

Trabajo de investigaciónLa presente investigación se orientó a determinar si la confianza organizacional se comportaba como mediadora de la relación entre el capital psicológico y la conducta de compartir conocimiento, para lo cual se realizó un estudio cuantitativo con un diseño transversal correlacional, con una muestra de 156 participantes, entre gerentes y empleados de empresas públicas y privadas del Departamento de Boyacá. Se evidenciaron correlaciones positivas entre las variables objeto de estudio y en virtud de los análisis de regresión lineal se encontró que la confianza organizacional media la relación entre el capital psicológico y la conducta de compartir conocimiento. Dado que la mediación encontrada fue parcial, se puede colegir que la confianza organizacional no es la única determinante de la relación entre estas variables; pueden existir otros factores igualmente considerables como el liderazgo. En conclusión, el presente documento visualiza el papel significativo de la confianza en entornos organizacionales, que finalmente se consolidará como una ventaja competitiva.1. RESUMEN 2. MARCO TEÓRICO 3. JUSTIFICACIÓN 4. PLANTEAMIENTO DEL PROBLEMA DE INVESTIGACIÓN 5. OBJETIVOS 6. VARIABLES 7. HIPÓTESIS 8. METODO 9. RESULTADOS 10. DISCUSIÓN 11. REFERENCIAS 12. APÉNDICESMaestríaMagister en Psicologí

Olanzapine Attenuates Cue-elicited Craving for Tobacco

Rationale: Recent biological conceptualizations of craving and addiction have implicated mesolimbic dopamine activity as a central feature of the process of addiction. Imaging, and pharmacological studies have supported a role for dopaminergic structures in cue-elicited craving for tobacco. Objective: If mesolimbic dopamine activity is associated with cue-elicited craving for tobacco, a dopamine antagonist should attenuate cueelicited craving for tobacco. Thus, the aim of the present study was to determine whether an atypical antipsychotic (olanzapine, 5 mg) decreased cue-elicited craving for tobacco. Method: Participants were randomly assigned to 5 days of pretreatment with olanzapine (5 mg; n=31) or were randomly assigned to 5 days of a matching placebo (n=28). Approximately 8 h after the last dose, participants were exposed to a control cue (pencil) followed by exposure to smoking cues. Participants subsequently smoked either nicotine cigarettes or de-nicotinized cigarettes. Results: Olanzapine attenuated cue-elicited craving for tobacco but did not moderate the subjective effects of smoking. Discussion: This study represents one of the first investigations of the effect of atypical antipsychotics on cue-elicited craving for tobacco. The results suggest that medications with similar profiles may reduce cue-elicited craving, which in turn, may partially explain recent observations that atypical antipsychotics may reduce substance use

Non-Iterative Characteristics Analysis for High-Pressure Ramp Loading

In the canonical ramp compression experiment, a smoothly-increasing load is applied to the surface of the sample, and the particle velocity history is measured at two or more different distances into the sample, at interfaces where the surface of the sample can be probed. The velocity histories are used to deduce a stress-density relation, usually using iterative Lagrangian analysis to account for the perturbing effect of the impedance mismatch at the interface. In that technique, a stress- density relation is assumed in order to correct for the perturbation, and is adjusted until it becomes consistent with the deduced stress-density relation. This process is subject to the usual difficulties of nonlinear optimization, such as the existence of local minima (sensitivity to the initial guess), possible failure to converge, and relatively large computational effort. We show that, by considering the interaction of successive characteristics reaching the interfaces, the stress-density relation can be deduced directly by recursion rather than iteration. This calculation is orders of magnitude faster than iterative analysis, and does not require an initial guess. Direct recursion may be less suitable for very noisy data, but it was robust when applied to trial data. The stress-density relation deduced was identical to the result from iterative Lagrangian analysis

The Effect of Olanzapine on Craving and Alcohol Consumption

Previous studies have indicated that olanzapine decreases craving after a priming dose of alcohol, that craving after a priming dose of alcohol is greater among individuals with the seven-repeat allele of the DRD4 variable number of tandem repeats (VNTR) polymorphism, and that the effect of olanzapine (a D2/D4 antagonist) is more pronounced among individuals with this allele. The present study tested the hypothesis that olanzapine may be differentially effective at reducing cue-elicited craving and differentially effective as a treatment for alcohol dependence over the course of a 12-week, randomized, placebo-controlled trial among individuals with and without the seven-repeat allele. Participants who met DSM IV criteria for alcohol dependence were randomly assigned to receive olanzapine (5 mg) or a placebo over the course of the trial. After 2 weeks of treatment, participants completed a cue reactivity assessment. The results suggested that participants who were homozygous or heterozygous for the seven (or longer)-repeat allele of the DRD4 VNTR responded to olanzapine with reductions in cue-elicited craving as well as reductions in alcohol consumption over the course of the 12-week trial, whereas individuals with the shorter alleles did not respond favorably to olanzapine