Reasoning About Lock Placements

Abstract. A lock placement describes, for each heap location, which lock guards the location, and under what circumstances. We formalize methods for reasoning about lock placements, making precise the interacting obligations between the program, the organization of the heap, and the placement of locks. Our methods capture realistic and subtle situations, such as the placement and correct use of speculative locks and lock assignments that change dynamically with updates to the heap. We present results for flat heaps with no structure, tree-structured heaps and a language of DAG-shaped heaps with bounded in-degree

A distributed camera system for multi-resolution surveillance

We describe an architecture for a multi-camera, multi-resolution surveillance system. The aim is to support a set of distributed static and pan-tilt-zoom (PTZ) cameras and visual tracking algorithms, together with a central supervisor unit. Each camera (and possibly pan-tilt device) has a dedicated process and processor. Asynchronous interprocess communications and archiving of data are achieved in a simple and effective way via a central repository, implemented using an SQL database. Visual tracking data from static views are stored dynamically into tables in the database via client calls to the SQL server. A supervisor process running on the SQL server determines if active zoom cameras should be dispatched to observe a particular target, and this message is effected via writing demands into another database table. We show results from a real implementation of the system comprising one static camera overviewing the environment under consideration and a PTZ camera operating under closed-loop velocity control, which uses a fast and robust level-set-based region tracker. Experiments demonstrate the effectiveness of our approach and its feasibility to multi-camera systems for intelligent surveillance

Concurrent data representation synthesis

We describe an approach for synthesizing data representations for concurrent programs. Our compiler takes as input a program written using concurrent relations and synthesizes a representation of the relations as sets of cooperating data structures as well as the placement and acquisition of locks to synchronize concurrent access to those data structures. The resulting code is correct by construction: individual relational operations are implemented correctly and the aggregate set of operations is serializable and deadlock free. The relational specification also permits a high-level optimizer to choose the best performing of many possible legal data representations and locking strategies, which we demonstrate with an experiment autotuning a graph benchmark

The Presence and Possibility of Moral Sensibility in Beginning Pre-Service Teachers

This paper presents research on the moral sensibility of six pre-service teachers in an undergraduate teacher education program. Using their reflective writing across their first two semesters of coursework as well as focus group interviews in their third semester as sources of data, the paper identifies and describes three distinctive types of moral sensibility and examines ways in which moral sensibility interacts with experiences in teacher education. Suggestions for explicitly incorporating the moral in pre-service teacher education are presented

Financial diversification before modern portfolio theory: UK financial advice documents in the late nineteenth and the beginning of the twentieth century

The paper offers textual evidence from a series of financial advice documents in the late nineteenth century and the early twentieth century of how UK investors perceived of and managed risk. In the world’s largest financial centre of the time, UK investors were familiar with the concept of correlation and financial advisers’ suggestions were consistent with the recommendations of modern portfolio theory in relation to portfolio selection strategies. From the 1870s, there was an increased awareness of the benefits of financial diversification - primarily putting equal amounts into a number of different securities - with much of the emphasis being on geographical rather than sectoral diversification and some discussion of avoiding highly correlated investments. Investors in the past were not so naïve as mainstream financial discussions suggest today

The SEC's "Fair Value" Standard for Mutual Fund Investment in Restricted Shares and Other Illiquid Securities

Mutual funds generally do not invest in venture capital, private equity, or restricted shares of public companies. Consequently, individuals who desire to invest in such securities are unable to do so through diversified mutual funds. In this paper, we identify public policies and regulations that discourage mutual fund involvement in the markets for illiquid equity. We also present evidence that changes in SEC policy caused mutual funds to retreat from investing in illiquid equity. Under the Investment Company Act of l940, the SEC requires mutual fund boards to determine and report the “fair value” of their investments in restricted shares and other illiquid equity claims. The SEC interprets fair value to mean value in current sale. Under the Investment Company Act, fair value reporting is a “certification” standard that presumes investors rely on the value representations of the fund board and its auditors. We consider whether alternatives to certification and current sale valuation could reduce barriers to mutual fund investment, without exposing individuals who invest in mutual funds to excessive risk or potential manipulation. To assess the effects of public policies, we analyze recent efforts of the SEC to apply the fair-value standard and examine court decisions arising from subsequent litigation. We also analyze the financial economics literature concerning discounts for illiquidity and the implications for valuing restricted shares. The paper concludes with a discussion of policy alternatives, including allowing funds to rely more on “transparency” in lieu of certification and allowing funds more latitude in determining and reporting the values of their illiquid securities.