ReCoDe: A Data Reduction and Compression Description for High Throughput Time-Resolved Electron Microscopy

Fast, direct electron detectors have significantly improved the spatio-temporal resolution of electron microscopy movies. Preserving both spatial and temporal resolution in extended observations, however, requires storing prohibitively large amounts of data. Here, we describe an efficient and flexible data reduction and compression scheme (ReCoDe) that retains both spatial and temporal resolution by preserving individual electron events. Running ReCoDe on a workstation we demonstrate on-the-fly reduction and compression of raw data streaming off a detector at 3 GB/s, for hours of uninterrupted data collection. The output was 100-fold smaller than the raw data and saved directly onto network-attached storage drives over a 10 GbE connection. We discuss calibration techniques that support electron detection and counting (e.g. estimate electron backscattering rates, false positive rates, and data compressibility), and novel data analysis methods enabled by ReCoDe (e.g. recalibration of data post acquisition, and accurate estimation of coincidence loss).Comment: 53 pages, 20 figure

APPLICATIONS OF GAME THEORY IN COUNTER-TERRORISM

Bachelor'sBACHELOR OF SCIENCE (HONOURS

BestPeer: A Self-Configurable Peer-to-Peer System

In a peer-to-peer (P2P) distributed system, nodes of equivalent capabilities and responsi- bilities pool their resources together to share information and services. However, most of the existing P2P systems such as Napster and Gnutella provide a coarse granularity of information sharing (i.e., file level) that ignore the content of the file. Moreover, a node's peers are typically statically defined. In addition, there is no support for nodes that are connected intermittently with temporary network addresses. In this paper, we present BestPeer, a prototype P2P system that we have implemented at the National University of Singapore. BestPeer is unique in several ways. First, it combines the power of mobile agents into P2P systems to perform operations at peers' sites. This facilitates content-based searching easily. Second, it is selfconfigurable, i.e., a node can dynamically optimize the set of peers that it can communicate directly with based on some optimization criterion. By keeping peers that provide most infor- mation or services in close proximity (i.e, direct communication), the network bandwidth can be better utilized and system performance can be optimized. Third, BestPeer provides a loca- tion independent global names lookup server to identify peers with dynamic (or unpredictable) IP addresses. In this way, several peers can always collaborate (or share resources) even if their IP addresses may be different at different occasions. We evaluated BestPeer on a cluster of 32 Pentium II PCs each running a Java-based storage manager. Our experimental results show that BestPeer provides excellent performance compared to traditional non-configurable models. Further experimental study reveals its superiority over Gnutella's protocol

Case study on shipbuilding and marine engineering employees' union.

This research seeks to explore the reasons why workers refuse unionisation despite enjoying double benefits (collective bargaining and non-collective bargaining) as well as the perceptions of the relative importance of non-collective bargaining to unionised workers. A case study on Shipbuilding and Marine Engineering Employees' Union (SMEEU) was conducted comprising of two surveys and one interview. Samples of the survey were obtained from 15 companies with union representation by SMEEU

A case study on the evacuation of deep mega underground development in Singapore

Subterranean space utilisation is considered as a viable solution to the lack of land space in Singapore. However, commercial development, with substantial floor area located at a significant depth underground is the first-of-its-kind in the world. Vertical exit shafts, one of the unique features of this underground development, serve as the only means of egress for occupants in the underground development. This feature is critical in ensuring safety of all occupants. Strategically located exit shafts with well-organised geometric layout will facilitate the overall evacuation process. This paper presents a case study that aims to optimise the locations of exit shafts in an underground development using STEPS simulation software.NRF (Natl Research Foundation, S’pore)Accepted versio

Structural Behaviour of Precast Beam-Column Sub-Assemblages with Cast-In-Situ Engineered Cementitious Composites under Column Removal Scenarios

This paper presents an experimental study on the structural behaviour of precast beam-column sub-assemblages under column removal scenarios, in which conventional concrete and engineered cementitious composites (ECC) were used in the cast-in-situ concrete topping and the beam-column joint. The specimens were restrained by horizontal and vertical load cells and tested under quasi-static loading condition. Experimental results indicate that at the initial stage ECC and steel reinforcement sustained tensile stresses compatibly and multiple cracking was observed in the ECC topping. When the tensile strain capacity of ECC was exhausted, major cracks were formed in the plastic hinge region, whereas at other sections ECC remained intact to transfer tensile stresses across cracks. Compared to conventional concrete, ECC resulted in more severe localisation of rotations in a limited region due to its tension-stiffening behaviour. Conclusions are drawn that application of ECC to structural topping and beam-column joints did not significantly enhance structural resistance of sub-assemblages under column removal scenarios. However, the calculated pseudo-static resistance of ECC sub-assemblage is greater than that of concrete specimen due to better energy-absorption capacity of ECC.Accepted versio

POEMS: A Transformable Architecture for Managing System Overload

In a typical organizational scenario, hundreds of personal computers (PCs) are used mainly for simple office tasks. Typically, a central database management system (DBMS) receives requests internally or externally through an Internet connection that serves as a backend of Web services. The unpredictability and fluctuations of requests could result in the overload of the DBMS. Existing load management systems assume nodes are fully dedicated to sharing loads, which could cause interruptions of the existing tasks running on the office PCs. In addition, data are statically partitioned and cached in the nodes permanently even though the system may be under-loaded. Moreover, the nodes that are involved in load-balancing are not allowed to dismiss the processes. In this paper, we describe a novel framework, POEMS, that is transformable between a client-server and Peer-to-Peer (P2P) architecture; it operates as a conventional DBMS under normal load condition without interrupting the nodes, and transforms to P2P operation mode for processing in a heavy-load condition. In contrast to traditional systems, all nodes in our proposed framework contribute the spare capacity of their hardware resources for data manipulation, and this is done without the need to install any DBMS at any of the nodes. Data are partitioned online and operators are distributed to nodes similarly. The effectiveness of POEMS query processing is achieved by node cooperation. POEMS allows processes or operators to be dismissed online, so a user can allocate more resources to his/her own operation tasks as and when the need arises. We evaluate the performance of our proposed system with a prototype implementation. The results suggest that POEMS is a feasible and effective approach for solving the system overload problem. 1

Answering similarity queries in peer-to-peer networks

10.1016/j.is.2004.09.003Information Systems31157-72INSY