Price Spikes in Electricity Markets: A Strategic Perspective

This paper aims to analyze the issue of price spikes in electricity markets through the lens of noncooperative game theory. The case we consider is Australia’s long established National Electricity Market (NEM). Specifically, we adapt von der Fehr and Harbord’s multi-unit auction model to settings that more closely reflect the structure of the NEM, showing that price spikes can be related to a specifiable threshold in demand.Electricity Markets, Spot Price Behaviour, Non-Cooperative Game Theory.

Functional analysis of the acetic acid resistance (aar) gene cluster in Acetobacter aceti strain 1023

Vinegar production requires acetic acid bacteria that produce, tolerate, and conserve high levels of acetic acid. When ethanol is depleted, aerobic acetate overoxidation to carbon dioxide ensues. The resulting diauxic growth pattern has two logarithmic growth phases, the first associated with ethanol oxidation and the second associated with acetate overoxidation. The vinegar factory isolate Acetobacter aceti strain 1023 has a long intermediate stationary phase that persists at elevated acetic acid levels. Strain 1023 conserves acetic acid despite possessing a complete set of citric acid cycle (CAC) enzymes, including succinyl-CoA:acetate CoA-transferase (SCACT), the product of the acetic acid resistance (aar) gene aarC. In this study, cell growth and acid production were correlated with the functional expression of aargenes using reverse transcription-polymerase chain reaction, Western blotting, and enzyme activity assays. Citrate synthase (AarA) and SCACT (AarC) were abundant in A. aceti strain 1023 during both log phases, suggesting the transition to acetate overoxidation was not a simple consequence of CAC enzyme induction. A mutagenized derivative of strain 1023 lacking functional AarC readily oxidized ethanol but was unable to overoxidize acetate, indicating that the CAC is required for acetate overoxidation but not ethanol oxidation. The primary role of the aar genes in the metabolically streamlined industrial strain A. aceti 1023 appears to be to harvest energy via acetate overoxidation in otherwise depleted medium

The Empirical Investigation of a Wiki based group system in organizations.

In this paper, success factors for wiki based information systems in organizations are discussed. Based on information system success factors which have been discussed in previous research, this study will present the conceptual framework of how to predict knowledge work intention on using a wiki based information system and what the wiki based information system’s success factors are by studying relationships between user satisfactions and IS service quality. In addition, the role of managerial support for increasing a user’s adoption of a wiki-based information system will be discussed, based on a user’s behavioral intention to use the wiki

Augmentation Backdoors

Data augmentation is used extensively to improve model generalisation. However, reliance on external libraries to implement augmentation methods introduces a vulnerability into the machine learning pipeline. It is well known that backdoors can be inserted into machine learning models through serving a modified dataset to train on. Augmentation therefore presents a perfect opportunity to perform this modification without requiring an initially backdoored dataset. In this paper we present three backdoor attacks that can be covertly inserted into data augmentation. Our attacks each insert a backdoor using a different type of computer vision augmentation transform, covering simple image transforms, GAN-based augmentation, and composition-based augmentation. By inserting the backdoor using these augmentation transforms, we make our backdoors difficult to detect, while still supporting arbitrary backdoor functionality. We evaluate our attacks on a range of computer vision benchmarks and demonstrate that an attacker is able to introduce backdoors through just a malicious augmentation routine.Comment: 12 pages, 8 figure

The Servant of Darkness

This work of creative fiction with a critical introduction has been written as a defense and culmination of my studies of Medieval Literature and creative writing at Texas A&M University. The critical introduction analyzes the history and purpose of fanfiction, the inspiration for my writing, and attempts to dialogue with the works and thoughts of J. R. R. Tolkien within the world he created in the genre of fantasy fiction. The story focuses on a villainous protagonist in Tolkien’s Middle Earth with the intent of demonstrating theological points such as the purpose of evil, reprobation, and predestination

Eliciting third person perspectives in social work case discussions:A device for reflective supervision?

Reflective supervision is widely recommended as an effective way to support social workers to think about their practice and to make better decisions. Although previous research has proposed methods of pursuing reflective supervision, little is known about how supervisors attempt this in actual supervision meetings. One proposed method for supervisors is to elicit third person perspectives so that social workers can consider a situation from different points of view. In this article, we examine this method by analysing audio recordings of 12 supervision meetings from one local authority Children and Families Social Work team. Using Conversation Analysis (CA), we explore supervisors’ attempts to elicit other people’s perspectives, focusing on how such requests were formed and how the social worker responded. We found 35 instances of supervisors attempting to elicit third person perspectives and identified four different ways that supervisors designed these enquiries. Supervisors oriented to two concerns, based on whether they enquired about a perspective that was currently established or projected into the future, and whether the information was verifiable through speech or actions, or imagined based on the other person’s thoughts or understanding. We draw on CA work on epistemics and stance to show how these different approaches have implications for what the social worker is expected to know and how both speakers orient to the accountability of the social worker. We conclude by considering the epistemic friction between the design of these enquiries, the relevance of professional accountability and the possibilities for pursuing reflective supervision in practice

Developing Cyberspace Data Understanding Using CRISP-DM for Host-based IDS Feature Mining

Current intrusion detection systems (IDS) generate a large number of specific alerts, but typically do not provide actionable information. Compounding this problem is the fact that many alerts are false positive alerts. This paper applies the Cross Industry Standard Process for Data Mining (CRISP-DM) to develop an understanding of a host environment under attack. Data is generated by launching scans and exploits at a machine outfitted with a set of host-based forensic data collectors. Through knowledge discovery, features are selected to project human understanding of the attack process into the IDS model. By discovering relationships between the data collected and controlled events, false positive alerts were reduced by over 91% when compared to a leading open source IDS. This method of searching for hidden forensic evidence relationships enhances understanding of novel attacks and vulnerabilities, bolstering ones ability to defend the cyberspace domain. The methodology presented can be used to further host-based intrusion detection research

Tooth Whitening Effects on Bracket Bond Strength In Vivo

Objective: To test the hypothesis that there is no difference between the bracket survival rate of brackets bonded to bleached and unbleached teeth. Materials and Methods: Thirty-eight patients who required comprehensive orthodontic treatment were included in the study. A split mouth technique was used with one arch exposed to in-office whitening gel containing 38% hydrogen peroxide for 30 minutes, while the unbleached arch served as the control. Patients were divided into two groups: Brackets bonded within 24 hours after bleaching and brackets bonded 2–3 weeks after bleaching. The bracket survival rate was computed using the log-rank test (Kaplan-Meier Analysis). Results: A significantly higher rate of bracket failure was found with bleached teeth (16.6%) compared with unbleached teeth (1.8%) after 180 days. Brackets bonded within 24 hours of bleaching resulted in significantly higher clinical failure (14.5%) compared with those bonded after 3 weeks (2.1%). Adhesive Remnant Index scores of failed brackets revealed that the majority of failure in bleached teeth occurred in the enamel/resin interface. Conclusions: The hypothesis was rejected. Brackets bonded within 24 hours after bleaching have a significantly higher risk for bond failure. Orthodontic bonding should be delayed for 2–3 weeks if patients have a history of in-office bleaching with 38% hydrogen peroxide

Metal stopping reagents facilitate discontinuous activity assays of the de novo purine biosynthesis enzyme PurE

The conversion of 5-aminoimidazole ribonucleotide (AIR) to 4-carboxy-AIR (CAIR) represents an unusual divergence in purine biosynthesis: microbes and nonmetazoan eukaryotes use class I PurEs while animals use class II PurEs. Class I PurEs are therefore a potential antimicrobial target; however, no enzyme activity assay is suitable for high throughput screening (HTS). Here we report a simple chemical quench that fixes the PurE substrate/product ratio for 24 h, as assessed by the Bratton-Marshall assay (BMA) for diazotizable amines. The ZnSO4 stopping reagent is proposed to chelate CAIR, enabling delayed analysis of this acid-labile product by BMA or other HTS method