22,577 research outputs found
Finding out how close source code files are to files in the Git version control system.
A lot of popular software is developed using a version control system. Historically systems such as RCS, CVS and Subversion were used, but a lot of developers have moved to Git. These systems have a lot of information available about the history of a file. When software is distributed, it is often distributed without this history information. In some situations it is important to find out how close a certain piece of software is to any given version in a version control system, for example for assessing copyright, security research or other provenance issues.
keywords: Git, software engineering, security, defect discovery, tls
Control/structure interaction during Space Station Freedom-Orbiter berthing
The berthing maneuver is essential for the construction and assembly of Space Station Freedom (SSF) and has a direct effect on the SSF assembly build up and SSF/Orbiter operations. The effects of flexible body dynamics coupled with the available control system may impose new requirements on the maneuver. The problem is further complicated by the effect of the SSF control system on the Shuttle Remote Manipulator System (SRMS). These effects will play a major role in the development of operational requirements which need to be identified and validated in order to assure total safety and maneuver execution during SSF construction. This paper presents the results of ongoing studies to investigate the Control/Structure Interaction (CSI) during the berthing operations. The problem is formulated in terms of multi-flex body equations of motion for SSF and the SRMS and on-orbit flight control systems for the SRMS and the SSF, which includes the Control Moment Gyro (CMG) and Reaction Control System (RCS) Attitude Control Systems (ACS). The SSF control system designs are based on the Preliminary Design Review (PDR) version of the Honeywell design. The simulation tool used for the analysis is briefly described and the CSI results are presented for given berthing scenarios
A C++-embedded Domain-Specific Language for programming the MORA soft processor array
MORA is a novel platform for high-level FPGA programming of streaming vector and matrix operations, aimed at multimedia applications. It consists of soft array of pipelined low-complexity SIMD processors-in-memory (PIM). We present a Domain-Specific Language (DSL) for high-level programming of the MORA soft processor array. The DSL is embedded in C++, providing designers with a familiar language framework and the ability to compile designs using a standard compiler for functional testing before generating the FPGA bitstream using the MORA toolchain. The paper discusses the MORA-C++ DSL and the compilation route into the assembly for the MORA machine and provides examples to illustrate the programming model and performance
Satellite system performance assessment for in-flight entertainment and air traffic control
Concurrent satellite systems have been proposed for IFE (In-Flight Entertainment) communications, thus demonstrating the capability of satellites to provide multimedia access to users in aircraft cabin. At the same time, an increasing interest in the use of satellite communications for ATC (Air Traffic Control) has been motivated by the increasing load of traditional radio links mainly in the VHF band, and uses the extended capacities the satellite may provide. However, the development of a dedicated satellite system for ATS (Air Traffic Services) and AOC (Airline Operational Communications) seems to be a long-term perspective. The objective of the presented system design is to provide both passenger application traffic access (Internet, GSM) and a high-reliability channel for aeronautical applications using the same satellite links. Due to the constraints in capacity and radio bandwidth allocation, very high frequencies (above 20 GHz) are considered here. The corresponding design implications for the air interface are taken into account and access performances are derived using a dedicated simulation model. Some preliminary results are shown in this paper to demonstrate the technical feasibility of such system design with increased capacity. More details and the open issues will be studied in the future of this research work
Time-Space Efficient Regression Testing for Configurable Systems
Configurable systems are those that can be adapted from a set of options.
They are prevalent and testing them is important and challenging. Existing
approaches for testing configurable systems are either unsound (i.e., they can
miss fault-revealing configurations) or do not scale. This paper proposes
EvoSPLat, a regression testing technique for configurable systems. EvoSPLat
builds on our previously-developed technique, SPLat, which explores all
dynamically reachable configurations from a test. EvoSPLat is tuned for two
scenarios of use in regression testing: Regression Configuration Selection
(RCS) and Regression Test Selection (RTS). EvoSPLat for RCS prunes
configurations (not tests) that are not impacted by changes whereas EvoSPLat
for RTS prunes tests (not configurations) which are not impacted by changes.
Handling both scenarios in the context of evolution is important. Experimental
results show that EvoSPLat is promising. We observed a substantial reduction in
time (22%) and in the number of configurations (45%) for configurable Java
programs. In a case study on a large real-world configurable system (GCC),
EvoSPLat reduced 35% of the running time. Comparing EvoSPLat with sampling
techniques, 2-wise was the most efficient technique, but it missed two bugs
whereas EvoSPLat detected all bugs four times faster than 6-wise, on average.Comment: 14 page
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