Exact Camera Location Recovery by Least Unsquared Deviations

We establish exact recovery for the Least Unsquared Deviations (LUD) algorithm of Ozyesil and Singer. More precisely, we show that for sufficiently many cameras with given corrupted pairwise directions, where both camera locations and pairwise directions are generated by a special probabilistic model, the LUD algorithm exactly recovers the camera locations with high probability. A similar exact recovery guarantee was established for the ShapeFit algorithm by Hand, Lee and Voroninski, but with typically less corruption

The vulnerable observer: Fear, sufferings and boundary crossing

In this contribution, Yunpeng Zhang responds to an earlier post by Qin Shao (see Building Trust and Boundary: Fieldwork in Shanghai) to provoke discussions on the dilemma and ethics of observing, witnessing and writing about vulnerable people. Challenging the ‘boundary’ setting efforts in researching contentious topics and in working with such people, Yunpeng reflects upon his own fieldwork research on Shanghai’s Expo-induced domicide, relating in particular to an episode that revolted his own subjectivity and agency. It is suggested that we take a radical path that views ourselves not as academic professionals but as persons with a particular set of knowledge, and that this way of thinking pushes us to ponder our civic and intellectual responsibilities for the people not as research subjects but as fellow citizens, writes Yunpeng Zhang

Squatting to end domicide? Resisting bulldozer urbanism in contemporary Shanghai

For millions of Shanghainese on the lower rung of society, the history of the great urban transformation in the city since the 1990s is written with their tears for the loss of their homes, communities and livelihood. In this paper, I argue for squatting as a straightforward, effective and potentially radical strategy to redress the displacees’ suffering, to take a more active and progressive control of the violent accumulation process and to challenge the hegemonic discourse of private homeownership that underpins the rapid transformation of Shanghai’s urban landscape. The argument is built upon an in-depth study of a family evicted by the World Expo 2010 and squatted in a resettlement apartment. Their framing of justice and entitlement, embedded in local cultural and moral universes, not only lends legitimacy to their squatting but also mobilises popular sympathy, both of which are conducive to effective resistance

Fault-Based Testing of Combining Algorithms in XACML 3.0 Policies

With the increasing complexity of software, new access control methods have emerged to deal with attribute-based authorization. As a standard language for attribute-based access control policies, XACML offers a number of rule and policy combining algorithms to meet different needs of policy composition. Due to their variety and complexity, however, it is not uncommon to apply combining algorithms incorrectly, which can lead to unauthorized access or denial of service. To solve this problem, this paper presents a fault-based testing approach for determining incorrect combining algorithms in XACML 3.0 policies. It exploits an efficient constraint solver to generate queries to which a given policy produces different responses than its combining algorithm-based mutants. Such queries can determine whether or not the given combining algorithm is used correctly. Our empirical studies using sizable XACML policies have demonstrated that our approach is effective

Proteomic and metabolomic analyses reveal metabolic responses to 3-hydroxypropionic acid synthesized internally in cyanobacterium Synechocystis sp. PCC 6803

Additional file 1: Figure S1. Comparison of cell growth of the WT and the engineered Synechocystis strains in this study

Blasting Vibration Monitoring and a New Vibration Reduction Measure

Vibration waves generated by blasting can cause shock to buildings. Different responses occur in different parts of the building. Therefore, a single standard is inaccurate. At the same time, methods to reduce vibration are needed. In this paper, the variation of peak particle velocity (PPV) and principal frequency was analyzed. The energy variation of blast vibration waves was analyzed by wavelet packet decomposition. A numerical model was established to verify the new vibration reduction measure. The results showed that the PPV on the walls increases with their height. The PPV and principal frequency of different structures of single-story brick-concrete buildings are different. The amplification factor of PPV does not change much when the principal frequency ratio is larger than 0.75. Measuring points at different heights have different sensitivities to blasting vibration waves of different principal frequencies. Therefore, different structures will respond differently to the same blasting operation. The PPV can be reduced by waveform interference. However, the cycle of blasting vibration waves decreases with increasing distance. Therefore, it is necessary to determine a reasonable interval to reduce the PPV. This requires further research