Nash-Cournot Equilibria in Power Markets on a Linearized DC Network with Arbitrage: Formulations and Properties

Extending a prior arbitrage-free model of Hobbs (2001), this article presents two models of an electric power market with arbitrage on a linearized DC network with a affine price functions. The two models represent a decentralized system involving bilateral contracts between producers and consumers in which the system operator's role is limited to providing transmission services. The two models differ in how arbitrage is handled. In the first model, the producers anticipate the effect of arbitrage upon prices at different locations (Stackelberg assumption), and therefore treat the arbitrage amounts as decision variables in their profit maximization problems. In the second model, the firms take the arbitrage quantities as inputs in their problems (Cournot assumption), and the arbitrager solves a separate profit maximization problem that takes the electricity prices and the transmission costs as inputs. In each model, we adopt a Nash-Cournot equilibrium as the solution concept for the game among producers. We show that the resulting equilibrium problems can be formulated as monotone mixed linear complementarity problems. Based on such a formulation, we obtain existence,uniqueness,and various quantitative properties of the equilibrium solutions to the models. It is also demonstrated that these two models of a bilateral market yield the same prices, producer outputs, and profits as a model of Cournot competition in a Poolco system,in which a system operator runs a centralized auction and buys all production, and then resells it to consumers. This result implies that Cournot competition among producers yields the same outcomes for two distinct market designs. Finally, we present a numerical example to illustrate the theoretical results.     

Influence of acute smoking exposure on the subsequent reinforcing value of smoking.

The reinforcing value of smoking (i.e., the degree to which a smoker will work to obtain smoking) after varying the magnitude of prior smoke exposure in smokers not trying to quit was examined. Eight men and 8 women participated in 5 sessions involving manipulation of prior exposure to smoking: 0, 2, 6, or 12 puffs after overnight smoking abstinence or ad-lib smoking before the session. After exposure, participants engaged in a computer task involving concurrent schedules of reinforcement for smoke puffs (16% all trials) versus money (4–64%). Only the greatest amount of prior exposure (ad lib) produced a significant reduction in subsequent responding for smoke puffs. No exposure condition significantly increased responding above that for 0 puffs, indicating no priming effect. By contrast, self-report measures of desire to smoke and amount of money participants would pay for a cigarette declined sharply with greater prior exposure. These measures were correlated only weakly with smoke-reinforced responding on the behavioral task, suggesting that subjective versus behavioral measures assess different dimensions of smoking's reward value. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New scales for the Devereux Adolescent Behavior Rating Scale.

Five new scales for the Devereux Adolescent Behavior Rating Scale (DAB), measuring acting out behaviors, withdrawn/timid behaviors, psychotic behaviors, neurotic/dependent behaviors, and heterosexual interests, were developed using item-level factor analyses. These new scales were developed after two of the four higher order scales previously developed in a substance-abuse sample were not replicated in a psychiatric-inpatient and day-treatment sample. Internal consistency analyses indicated that the five new scales reliably assess behavior in a sample with diverse problems. The new scales were found to be substantially concordant with narrowband and broadband dimensions of adolescent psychopathology identified in previous studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Once a boring task always a boring task? Interest as a self-regulatory mechanism.

Proposed a process through which individuals regulate their motivation to perform necessary but uninteresting activities over time. If committed to continuing, individuals may engage in interest-enhancing strategies that can change the activity into something more positive to perform. In Study 1, Ss performed novel tasks and generated strategies to make regular performance interesting. In Study 2, Ss actually used these strategies primarily in conditions indicating a self-regulatory attempt: The task was currently boring, there was a perceived reason to continue (alleged health benefit), and a relevant strategy was available. Strategy use was associated with a change in activity definition and greater likelihood of subsequently performing the activity. In Study 3, Ss' beliefs about how to maintain motivation to perform more everyday activities emphasized the importance of regulating interest relative to other self-regulatory strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Marital Satisfaction Questionnaire for Older Persons.

Conducted 5 studies to construct and psychometrically evaluate a marital satisfaction questionnaire for older persons. The questionnaire content was generated and refined in Study 1, temporal stability was evaluated in Study 2, and criterion-related validity was examined in Study 3. Norms, factor structure, and construct validity of the questionnaire were established in Study 4. The degree to which scores on the questionnaire predicted observer ratings of marital interactions during an analog problem-solving situation was examined in Study 5. The final questionnaire consists of 24 items with 1 major and 2 minor factors. Factor scores and a total Marital Satisfaction Scale score were found to be homogeneous, temporally stable, and significantly correlated with multiple measures of marital adjustment, life satisfaction, perceived spouse behaviors, and observer ratings of marital communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Textons, visual pop-out effects, and object recognition in infancy.

Five experiments were conducted to determine whether primitive perceptual features, or textons, which B. Julesz (1984) identified in studies of texture segregation with adults, also affect object recognition early in development. Three-month-old infants discriminated Ts and Ls composed of overlapping line segments from +s but not from each other in a delayed-recognition test after 24 hrs; however, Ts and Ls were discriminated from each other after only 1 hr. In a priming paradigm, Ts, Ls, and +s were discriminated from one another after 2 wks. In succeeding experiments, infants exhibited adultlike visual pop-out effects in both delayed recognition and priming paradigms, detecting an L in the midst of 6 +s and vice versa; these effects were symmetrical. The pop-out effects apparently resulted from parallel search: Infants failed to detect 3 Ls among 4 +s. Clearly, some of the same primitive units that have been identified as the building blocks of adult visual perception underlie object recognition early in infancy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial disorientation blocks reliable goal location on a plus maze but does not prevent goal location in the Morris maze.

Cue control in spatial learning was investigated in a plus maze and a Morris maze. Rats transported in opaque containers with prior rotation to a plus maze, but not a Morris maze, could not find a goal defined by external cues. Rats transported in clear containers without rotation found the goal in both mazes. In the Morris maze, goal location was readily relearned following cue removal by rats in clear containers but not by rats in the opaque/rotation group. B. L. McNaughton et al's (1996) theory that during spatial learning sensory information is bound to preconfigured internal maps in the hippocampus, whose metric is self-notion and whose orientation depends on input from an inertial based head direction system, may explain this study's findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of computer-generated facial composites.

Two studies examined the effectiveness of the Mac-a-Mug Pro, a computerized facial composite production system. In the first study, college freshmen prepared from memory composites of other students and faculty from their former high schools. Other students who had attended the same high schools could not recognize the composites of either students or faculty members when the composites of individuals known to them (n?=?10) were mixed with composites of a large number (n?=?40) of strangers. Neither preparer familiarity with the target, preparer-assessed composite quality, nor viewer familiarity predicted composite recognition. Study 2 indicated that naive witnesses who viewed the composites could not select the people depicted in the composites from photo lineups (1 target and 4 foils) . The results raise questions about the efficacy of composite systems as tools to promote recognition of suspects in criminal contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensory perception of fat in common foods using two scaling methods

Seventy-three subjects evaluated fat content and preference for six different foods using a ranking task and a line scale, and the results from the two methods were compared. The foods included milk, pudding, mashed potatoes, and chicken spread (0–30% added fat), scrambled eggs (0–50% added fat) and a savory snack (low-high in added fat). Samples within a series were formulated to minimize appearance and flavor differences. The perception of fat in these foods appeared to be system-specific. Subjects effectively judged increasing fat content in the milk, pudding, potato, and snack samples, but could not reliably judge fat content in the chicken spreads and scrambled eggs. The hedonic ratings were unrelated to the ability to perceive fat in these foods. Both scaling techniques were effective in scaling these perceptions.