Recovering traceability links between code and documentation

Software system documentation is almost always expressed informally in natural language and free text. Examples include requirement specifications, design documents, manual pages, system development journals, error logs, and related maintenance reports. We propose a method based on information retrieval to recover traceability links between source code and free text documents. A premise of our work is that programmers use meaningful names for program items, such as functions, variables, types, classes, and methods. We believe that the application-domain knowledge that programmers process when writing the code is often captured by the mnemonics for identifiers; therefore, the analysis of these mnemonics can help to associate high-level concepts with program concepts and vice-versa. We apply both a probabilistic and a vector space information retrieval model in two case studies to trace C++ source code onto manual pages and Java code to functional requirements. We compare the results of applying the two models, discuss the benefits and limitations, and describe directions for improvements.     

New TiNiSi-type RMgAg and RMgPd with R=Ca, Yb, and MgZn2-type Ca(Mg,Ag)2 compounds

The phases CaMgAg, YbMgAg, CaMgPd, and YbMgPd were synthesized by melting the constituent metals in sealed tantalum crucibles and by annealing at 1023 K. All the samples were homogeneous, and the crystallographic analysis, which was performed by powder and singlecrystal techniques, shows that the four compounds are isotypic and belong to the orthorhombic TiNiSi type. Magnetic measurements showed that YbMgAg and YbMgPd behave like Pauli paramagnets, according to the divalency of Yb in both phases. Within the Ca-Mg-Ag system, the existence range of the MgZn₂-type phases in the Mg-rich CaMg_2−x Ag _x pseudobinary system goes from CaMg₂ to CaMg_1.6Ag_0.4. Another stability region of the MgZn₂ structure occurs around the Ag-rich composition (Ca_0.94Mg_0.06)(Ag_1.60Mg_0.40), where magnesium replaces both the Ca and Ag atoms.     

Detecting buffer overflow via automatic test input data generation

Buffer overflows cause serious problems in various categories of software systems. In critical systems, such as health-care, nuclear or aerospace software applications, a buffer overflow may cause severe threats to humans or severe economic losses. If they occur in network or security applications, they can be exploited to gain administrator privileges, perform system attacks, access unauthorized data, or misuse the system. This paper proposes a combination of genetic algorithms, linear programming, evolutionary testing, and static and dynamic information to detect buffer overflows. The newly proposed test input generation process avoids the need for human intervention to define and tune genetic algorithm weights and therefore it becomes completely automated. The process that guides the genetic search towards the detection of buffer overflow relies on a fitness function that takes into account static and dynamic information. Reported results of our case studies, consisting of two sets of open-source programs show that the new process and fitness function outperform previously published approaches.     

Optical detection of the Coriolis force on a silicon micromachined gyroscope

In this paper, we report on the optical characterization of a micromachined gyroscope prototype for automotive applications, by means of feedback interferometry. In order to directly detect the rotation-induced Coriolis force, we have developed a compact and stable interferometric setup, which has been positioned inside a small vacuum bell, mounted on a rotating table. By this setup, which has a noise limit of the order of 10/sup -11/ m/(Hz)/sup 1/2/, we have measured the gyro responsivity curve, demonstrating the feasibility of the optical interferometric detection of the in-plane response of a MEMS sensor. In addition, we have carried out the full mechanical characterization of the device at different pressures, and we have performed the matching of the gyro resonance frequencies by the interferometric monitoring. Our gyro had a resonance frequency of 3986 Hz for both axes after tuning; at a pressure of 7 10/sup -2/ torr, the quality factor were Q=18000 for the driving axis and Q=1800 for the sensing axis, while the measured responsivity was 7 10/sup -10/ m/(/spl deg//s). The optical characterization represents an important feedback to the designer and is especially powerful in the case of prototypes for which the on-board electronics is not yet available.     

Software assessment using metrics: A comparison across large C++ and Java systems

This paper presents an assessment method to evaluate the quality of object oriented software systems. The assessment method is based on source code abstraction, object–oriented metrics and graphical representation. The metrics used and the underlying model representing the software are presented. The assessment method experiment is part of an industrial research effort with the Bell Canada Quality Engineering and Research Group. It helps evaluators assess the quality and risks associated with software by identifying code fragments presenting unusual characteristics. The assessment method evaluates object–oriented software systems at three levels of granularity: system level, class level and method level. One large C++ and eight Java software systems, for a total of over one million lines of code, are presented as case studies. A critical analysis of the results is presented comparing the systems and the two languages. This revised version was published online in June 2006 with corrections to the Cover Date.     

Non-intercepting electron beam transverse diagnostics with optical diffraction radiation at the DESY FLASH facility

Linear colliders (LCs) and short wavelength free electron lasers (FELs) require ultra-high brilliant electron beams of so much power density that no intercepting device can sustain it. The development of suitable beam diagnostics, non-invasive and non-intercepting, is necessary to measure the properties of such beams.Optical diffraction radiation (ODR) is considered as one of the most promising candidates, as testified by the interest of many laboratories all around the world.An experiment based on the detection of ODR has been set-up at DESY FLASH Facility and it is under operation to measure the electron beam transverse parameters. The radiation is emitted by a high energetic electron beam passing through a sub-millimeter slit, opened on a screen made of aluminum deposited on a silicon substrate. Radiation is then detected by a low noise, high sensitivity CCD camera.We report here the preliminary results for a 680 MeV electron beam energy going through a 0.5 mm slit.     

The EMMA2 multiprocessor operating system

The EMMA2

1 EMMA is a registered trademark of Elsag—Elettronica San Giorgio.

parallel architecture is a network of nodes, named 'Regions': each region is based on two shared-memory hierarchical bus levels, on which a large series of monocpu, multicpu and specialized I/O boards can be inserted, grouped in 'Families'. Its typical applications are Image processing, pattern recognition and artificial intelligence, characterized by intensive computation requirements, real-time constraints and good price-performance ratio for building large industrial systems. This paper presents the main characteristics of the EMMA2 parallel operating system, highlighting the internal organization and mechanisms offering the parallel co-operation model for user programs. Section 1 briefly introduces the overall hardware architecture. It allows application partitioning into parallel independent subsystems, on two levels of computation: the lower level (family) is dedicated to massive number crunching, while the upper (region) permits the interaction of these lower machines. Section 2 deals with the system software environment, based on a host-target configuration: the host is mainly devoted to machine control, system monitoring, program development and debugging in a multi-user environment. Sections 3, 4 and 5 describe respectively the fundamental concepts of the operating system internal organization and the basic mechanisms with respect to the machine architecture; the basic functions that constitute the internal layers and services; the resulting parallel programming and co-operation model and the typical mapping rules of algorithms to this architecture, completed with some examples of their functionalities. The most important aspect of the EMMA2 operating system is the fact that it offers a uniform interface to user tasks, independently of their allocation on the target machine. Objects managed by system services can be referred to via logical names. Code for system services is distributed among processors and resides on a private read-only memory. The operating system's data reside in shared memory only for system functions that need to be distributed, while private functions are based on different copies of data in private memories. Section 6 gives more details on the most relevant EMMA2 industrial applications, also showing their mapping to the parallel architecture and some performance-related information. Section 7 contains a brief outline of the novel architecture currently in development and of the subsequent OS Improvements. In conclusion, we report some considerations about the present status of the EMMA2 system, compared with some other well-known architectures, and about research efforts for its future evolution.     

Detection of Pathological Markers of Neurodegenerative Diseases following Microfluidic Direct Conversion of Patient Fibroblasts into Neurons

Neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease are clinically diagnosed using neuropsychological and cognitive tests, expensive neuroimaging-based approaches (MRI and PET) and invasive and time-consuming lumbar puncture for cerebrospinal fluid (CSF) sample collection to detect biomarkers. Thus, a rapid, simple and cost-effective approach to more easily access fluids and tissues is in great need. Here, we exploit the chemical direct reprogramming of patient skin fibroblasts into neurons (chemically induced neurons, ciNs) as a novel strategy for the rapid detection of different pathological markers of neurodegenerative diseases. We found that FAD fibroblasts have a reduced efficiency of reprogramming, and converted ciNs show a less complex neuronal network. In addition, ciNs from patients show misfolded protein accumulation and mitochondria ultrastructural abnormalities, biomarkers commonly associated with neurodegeneration. Moreover, for the first time, we show that microfluidic technology, in combination with chemical reprogramming, enables on-chip examination of disease pathological processes and may have important applications in diagnosis. In conclusion, ciNs on microfluidic devices represent a small-scale, non-invasive and cost-effective high-throughput tool for protein misfolding disease diagnosis and may be useful for new biomarker discovery, disease mechanism studies and design of personalised therapies.     

Behavior of Salmonella during fermentation,drying and storage of cocoa beans

Due to cocoa being considered a possible source of Salmonella contamination in chocolate, the behavior of Salmonella during some cocoa pre-processing stages (fermentation, drying and storage) was investigated. The fermentation process was carried out on a pilot scale (2 kg beans/box) for 7 days. Every day a fermentation box was inoculated with a Salmonella pool (ca. 4 log MPN/g). The results showed that Salmonella did not affect (P > 0.05) the growth of the main microorganism groups involved in cocoa fermentation. On the other hand, the pathogen was influenced (P < 0.05) by yeast, acetic acid bacteria and pH. In spite of Salmonella showing counts ≤ 1 log MPN/g in the first days, at the end of fermentation it grew in all samples, reaching counts as high as 7.49 log MPN/g. For drying and storage, cocoa beans were inoculated during the fermentation (experiment A) or during the drying (experiment B). In these stages the decline of the water activity affected the pathogen behavior. In experiment A during the drying, Salmonella count increased in most of the samples. In experiment B either a slight growth or no growth in the samples inoculated up to 48 h was observed, whereas the other samples showed reductions from the initial count. After 30 days of storage at room temperature, the water activity decreased to 0.68, and reductions of Salmonella ranged from 0.93 to 2.52 log MPN/g. Despite the reductions observed during the storage, the pathogen was detected even after 120 days. Therefore, the results showed that Salmonella growth or survival depends on when the contamination occurs.