Automated Refactoring of Nested-IF Formulae in Spreadsheets

Spreadsheets are the most popular end-user programming software, where formulae act like programs and also have smells. One well recognized common smell of spreadsheet formulae is nest-IF expressions, which have low readability and high cognitive cost for users, and are error-prone during reuse or maintenance. However, end users usually lack essential programming language knowledge and skills to tackle or even realize the problem. The previous research work has made very initial attempts in this aspect, while no effective and automated approach is currently available. This paper firstly proposes an AST-based automated approach to systematically refactoring nest-IF formulae. The general idea is two-fold. First, we detect and remove logic redundancy on the AST. Second, we identify higher-level semantics that have been fragmented and scattered, and reassemble the syntax using concise built-in functions. A comprehensive evaluation has been conducted against a real-world spreadsheet corpus, which is collected in a leading IT company for research purpose. The results with over 68,000 spreadsheets with 27 million nest-IF formulae reveal that our approach is able to relieve the smell of over 99\% of nest-IF formulae. Over 50% of the refactorings have reduced nesting levels of the nest-IFs by more than a half. In addition, a survey involving 49 participants indicates that for most cases the participants prefer the refactored formulae, and agree on that such automated refactoring approach is necessary and helpful

On Max-SINR Receiver for Hexagonal Multicarrier Transmission Over Doubly Dispersive Channel

In this paper, a novel receiver for Hexagonal Multicarrier Transmission (HMT) system based on the maximizing Signal-to-Interference-plus-Noise Ratio (Max-SINR) criterion is proposed. Theoretical analysis shows that the prototype pulse of the proposed Max-SINR receiver should adapt to the root mean square (RMS) delay spread of the doubly dispersive (DD) channel with exponential power delay profile and U-shape Doppler spectrum. Simulation results show that the proposed Max-SINR receiver outperforms traditional projection scheme and obtains an approximation to the theoretical upper bound SINR performance within the full range of channel spread factor. Meanwhile, the SINR performance of the proposed prototype pulse is robust to the estimation error between the estimated value and the real value of time delay spread.Comment: 6 pages. The paper has been published in Proc. IEEE GLOBECOM 2012. Copyright transferred to IEEE. arXiv admin note: text overlap with arXiv:1212.579

On the Management of Scientific Research Work in Colleges and Universities of Western Areas

According to the existing condition analysis of academic research management in colleges and universities of the western areas, pointing out there being some existing problems at present, and putting forward to the countermeasures solving these problems. Thinking, as for the colleges and universities of the western areas, on the management of academic research work, are supposed to grasp the complication of it, highlight the local unique features, strengthen the ability of serving local economic, and take an important part in the local economic development

Costly External Finance: Implications for Capital Markets Anomalies

In a frictionless world, investment is perfectly elastic to changes in the discount rate. With financial frictions, investment is less elastic, meaning that a given magnitude of change in investment is associated with a higher magnitude of change in the discount rate. Equivalently, investment is a more powerful predictor of future stock returns. Consistent with this prediction, we document that the asset growth, external finance, and accrual anomalies in the cross-section of stock returns are much stronger in financially more constrained firms than in financially less constrained firms. Further tests show that this effect of financial constraints is distinct from the effect of financial distress and the effect of limits of arbitrage on the magnitude of the anomalies.