Office of Bureaucritic Imagination: State of Exception

The "Office for Bureaucritic Imagination - State of Exception" is a participatory speculative performance1 to design new laws and rethink alternative forms of political engagement. Together with designers, city municipality, politicians, local associations and citizens, the office provides opportunities for productive deliberations - where public and private interests are bridged and opinions are exchanged. Thus forming the basis for new futures to be imagined and perhaps enforced

Distinct Scaling Regimes of Energy Release Dynamics in the Nighttime Magnetosphere

Based on a spatiotemporal analysis of POLAR UVI images, we show that the auroral emission events that initiate equatorward of the isotropic boundary (IB) obtained from a time-dependent empirical model, have systematically steeper power-law slopes of energy, power, area and lifetime probability distributions compared to the events that initiate poleward of the IB. The low-latitude group of events contains a distinct subpopulation of substorm-scale disturbances violating the power-law behavior, while the high latitude group is described by nearly perfect power-law statistics over the entire range of scales studied. The results obtained indicate that the inner and outer portions of the plasma sheet are characterized by substantially different scaling regimes of bursty energy dissipation suggestive of different physics in these regions.Comment: 11 pages, 2 figures, 2 table

Simultaneous structural and control optimization via linear quadratic regulator eigenstructure assignment

A method for simultaneous structural and control design of large flexible space structures (LFSS) to reduce vibration generated by disturbances is presented. Desired natural frequencies and damping ratios for the closed loop system are achieved by using a combination of linear quadratic regulator (LQR) synthesis and numerical optimization techniques. The state and control weighing matrices (Q and R) are expressed in terms of structural parameters such as mass and stiffness. The design parameters are selected by numerical optimization so as to minimize the weight of the structure and to achieve the desired closed-loop eigenvalues. An illustrative example of the design of a two bar truss is presented

Hybrid approach for localization in anisotropic sensor networks

In many real-world applications including agricultural, meterological, military applications, etc, localization techniques are widely used to estimate the geographic locations of sensor nodes based on the precision positions of a few anchors equipped with special hardware. Existing localization algorithms mainly try to improve their accuracy in position estimation by using various heuristic-based or mathematical techniques. Every node in the network follows the same technique to find its physical location. However, each individual method with its own strength can only outperform the others in some but not all nodes. Based on this observation, we develop a hybrid approach for the localization problem. Each node collects the same kind of information. By analysing the information, a node can decide what is the best localization algorithm to use. Different nodes can make their own decisions. Our simulation results reveal that the hybrid approach is effective that it outpeforms existing algorithms. To the best of our knowledge, our work presents the first effort in solving the absolute localization problem by adopting a hybrid approach. © 2006 IEEE.published_or_final_versio

BlueGame - A bluetooth enabled multi-player and multi-platform game: An experience report

Computer games on mobile devices including cellular phones or handheld computers have become a fast expanding industry due to the recent advance in hardware and software supports. Most large mobile game and handheld vendors mainly focus on improving the interactivity and visual effects of, commonly single-user, mobile games. In this project, we carefully designed and then implemented an interactive multi-player action game, namely the BlueGame, transferrable between different computing platforms supported by the Bluetooth wireless technology. In addition to individual user's convenience to continue the multi-player game, our BlueGame prototype highlighted certain shortcomings of the existing Bluetooth technology, and more importantly our valuable experience gained for future wireless game development. ©2006 IEEE.published_or_final_versio

Improving localization in wireless sensor networks with an evolutionary algorithm

Wireless sensor networks are highly useful for many location-sensitive applications including environmental monitoring, military applications, disaster management, etc. Localization in wireless sensor networks concerns about the precise estimation of node positions given a relatively small portion as anchor nodes with their absolute positions predetermined. Intrinsically, localization is an unconstrained optimization problem based on various distance/path measures. Most of the existing work focus on increasing the accuracy in position estimation typically by using different heuristic-based or mathematical techniques. On the other hand, there were many complex optimization problems successfully tackled by the nature inspired search algorithms including the ant-based or genetic algorithms. In this paper, we propose to adapt an evolutionary approach, namely a microgenetic algorithm, and integrate as a post-optimizer into some existing localization techniques such as the Ad-hoc Positioning System (APS) to further improve their position estimation. Clearly, our proposed MGA is so adaptable that it can easily be integrated into other localization methods. More importantly, the remarkable improvements obtained by the prototype of our proposed evolutionary optimizer on certain anisotropic topologies of our simulation tests prompt for further investigation. © 2006 IEEE.published_or_final_versio

Reclamation Ground Settlement Monitoring by Using GPS and Other Positioning Technologies at ShenZhen Airport.

Hong Kong is a small territory of about 1070 km2 . There is an ever-increasing demand for land to cope with her increasing development. Typical geology in Hong Kong under the seabed comprises a layer of soft marine deposit of variable thickness of up to 20 m, overlying alluvium, residual soil, decomposed rock and bedrock. However, the marine deposit is too soft to support any structures. Conventional reclamation practice in Hong Kong is to dredge the marine deposit, build the seawalls and fill the enclosed space by sand. This conventional approach has many shortcomings. A research project was undertaken by The University of Hong Kong to develop a vacuum preloading technique that is environmentally safe to improve the engineering properties of the thick layer of soft marine deposits so that they can be kept in place during land reclamation. As a result, the environmental problems relating to dredging can be completely eliminated. A vacuum preloading test near the Shenzhen Airport was carried out as part of a very large research program. Sub-surface field instrumentation comprised piezometers, inclinometers, extensometers and pressure cells to monitor the performance of the vacuum system and the physical changes of the marine deposit during vacuum preloading. Surface settlement was monitored using 3 units of high precision GPS equipment throughout the test for checking against the sub-surface monitored movement. It is necessary to use a fully automatic system like GPS for replacing conventional survey because the test was carried out over water, which was difficult to access and the test was carried out over a very long period of 4 months. This paper reports the use of GPS for reclamation ground settlement monitoring and demonstrates cm-level positioning results through experimental trials. The results also agree very well with the sub-surface settlement readings.published_or_final_versio

Tropical nature reserves are losing their buffer zones, but leakage is not to blame.

Tropical forests provide important ecosystem services to humanity, yet are threatened by habitat loss resulting from deforestation and land-use change. Although reserves are considered the cornerstones of conservation efforts in the tropics, their efficacy remains equivocal. One question that remains unresolved is whether leakage - the unanticipated displacement of deforestation from inside reserves into the unrestricted zones just beyond a reserve's administrative boundary - is common around tropical forest reserves, or whether the zones are acting as buffers between the protected area and the outside world. To resolve this question, we used the Landsat-derived Global Forest Change dataset to estimate deforestation rates between 2000 and 2012 inside and outside of 60 nature reserves spread across the tropics. Deforestation rates inside reserves (within 5km of the administrative boundary) were generally lower than those immediately outside the reserves (i.e. in buffer zones 0-10km from the boundary), suggesting that reserves are effective at protecting forests. We hypothesised that leakage would result in greater deforestation rates in reserve buffer zones than in the broader reserve landscapes, but such a pattern was observed in only five African sites, suggesting that leakage does not often occur on the edge of established reserves. However, roughly 80% of reserves experienced deforestation rates that increased gradually from their interiors to the outer periphery of their buffer zones. Thus, while leakage may not be a pervasive phenomenon around tropical reserves worldwide, tropical reserves are often losing their buffer zones, resulting in increased isolation that could have ramifications for ecosystem services provisioning and tropical conservation strategies.We thank the Keasbey Memorial Foundation for their support of G.V.L.’s program of study at Cambridge. We thank Bill Laurance and Mark Mulligan for helpful discussions about the work. We also thank Marion Pfeifer, Xiuzhi Chen, Jung-Tai Chao, Mark Balman, Antonio Trabucco, Megan MacDowell, Beatriz Beisiegel, Joseph Wright, and Patrick Jansen (see Table A.1) for generously providing the shapefiles of various reserve boundaries required for this study.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.envres.2015.11.00

Sonic hedgehog regulates the proliferation, differentiation, and migration of enteric neural crest cells in gut

Enteric neural crest cells (NCCs) migrate and colonize the entire gut and proliferate and differentiate into neurons and glia of the enteric nervous system in vertebrate embryos. We have investigated the mitogenic and morphogenic functions of Sonic hedgehog (Shh) on enteric NCCs in cell and organ culture. Enteric NCCs expressed Shh receptor Patched and transcripts encoding the Shh signal transducer (Gli1). Shh promoted the proliferation and inhibited the differentiation of NCCs. The pro-neurogenic effect of glial cell line-derived neurotrophic factor (GDNF) on NCCs was abolished by Shh. In gut explants, NCCs migrated from the explants onto the adjacent substratum if GDNF was added, whereas addition of Shh abolished this migration. Neuronal differentiation and coalescence of neural crest-derived cells into myenteric plexuses in explants was repressed by the addition of Shh. Our data suggest that Shh controls the proliferation and differentiation of NCCs and modulates the responsiveness of NCCs toward GDNF inductions.published_or_final_versio