The ALICE Silicon Pixel Detector Control and Calibration Systems

The work presented in this thesis was carried out in the Silicon Pixel Detector (SPD) group of the ALICE experiment at the Large Hadron Collider (LHC). The SPD is the innermost part (two cylindrical layers of silicon pixel detec- tors) of the ALICE Inner Tracking System (ITS). During the last three years I have been strongly involved in the SPD hardware and software development, construction and commissioning. This thesis is focused on the design, development and commissioning of the SPD Control and Calibration Systems. I started this project from scratch. After a prototyping phase now a stable version of the control and calibration systems is operative. These systems allowed the detector sectors and half-barrels test, integration and commissioning as well as the SPD commissioning in the experiment. The integration of the systems with the ALICE Experiment Control System (ECS), DAQ and Trigger system has been accomplished and the SPD participated in the experimental December 2007 commissioning run. The complexity of the detectors, the high number of subcomponents and the harsh working environment make necessary the development of a control system parallel to the data acquisition. This online slow control, called Detector Control System (DCS), has the task of controlling and monitoring all hardware and software components of the detector and of the necessary infrastructures. The latter include the power distribution system, cool ing, interlock system, etc. In this scenario, the DCS assumes a key role. Its functionalities have extended well over the simple control and monitoring of the experiment. DCS, nowadays, are highly advanced and automated online data acquisition systems, with less stringent requirements compared to the DAQ. Moreover the SPD DCS has the unique feature of not only controlling but also operating the SPD front-end electronics. These requirements impose a high level of synchronization between the system components and a fast system response. The DCS, in this case, is a fundamental component for the detector calibration. The SPD DCS should be operated in the ALICE DCS framework hence a series of integration constraint should be applied to the system. Furthermore, in complex experiments such as ALICE, the detector operation is tightly bound to the connection and integration of the various systems such as DAQ, DCS, trigger system, Experiment Control System (ECS) and Offline framework. The operation of the SPD front-end electronics and services should be done at various levels of integration. At the first and bottom level it is required that each system runs safely and independently. At the second level the subsystem controls should be merged to form a unique entity. At this stage the components operation should be synchronized to reach the full detector operation. The third level requires the integration of the SPD control in the genera l ALICE DCS/ECS. These requirements have been fulfilled by designing the DCS with two main software layers. On the bottom a Supervisory Control And Data Acquisition (SCADA) layer controls and monitors the equipments. It is based on a commercial application, PVSS, and it also responsible of provide an user interface to the subsystem components. On top a Finite State Machine (FSM) Layer performs the logical connection between the SPD subsystems and it connects the SPD DCS with the ALICE DCS and ECS. PVSS is designed for slow control applications and it is not suitable for the direct control of the fast SPD front-end electronics. I designed a Front-End Device Server (FED Server) to interface the SCADA layer with the front-end electronics. The server receives macro-instructions from the SCADA and it operates autonomously the complex front-end electronics. The complexity of the detector calibration requires a high automation level and the integration of the calibration system with the ALICE calibration framework. In order to satisfy these requirements and provide the user with a simple and versatile interface, I decided to foresee two calibration scenarios. A calibration scenario, named DAQ ACTIVE, allows the fast detector calibration but it needs the control of the full detector and subsystems. A second calibration scenario, named DCS ONLY, slower than the DAQ ACTIVE scenario, allows the calibration of a detector partition without interference with the normal detector operation. The control and calibration systems have been used to characterize and test the SPD components before and after the integration in the detector, both in laboratory (DSF) and in the ALICE environment. Some calibration and control systems application examples as well as a brief overview of the detector performance evaluated during the commissioning phases are reported

Polynomial conjunctive query rewriting under unary inclusion dependencies

Ontology-based data access (OBDA) is widely accepted as an important ingredient of the new generation of information systems. In the OBDA paradigm, potentially incomplete relational data is enriched by means of ontologies, representing intensional knowledge of the application domain. We consider the problem of conjunctive query answering in OBDA. Certain ontology languages have been identified as FO-rewritable (e.g., DL-Lite and sticky-join sets of TGDs), which means that the ontology can be incorporated into the user's query, thus reducing OBDA to standard relational query evaluation. However, all known query rewriting techniques produce queries that are exponentially large in the size of the user's query, which can be a serious issue for standard relational database engines. In this paper, we present a polynomial query rewriting for conjunctive queries under unary inclusion dependencies. On the other hand, we show that binary inclusion dependencies do not admit polynomial query rewriting algorithms

The changing role of the international community in the achievement of the MDG goals in Bolivia

Millennium Development Goal number 8 (MDG8) concerns those external flows (Official Development Assistance, trade and debt relief) that ought to help developing countries achieve the MDGs by 2015. This paper reviews the role of these MDG8-related external flows in the case of Bolivia. Riding on high international prices for its major exports, and on fiscal expansion, remittances and debt forgiveness, Bolivia has experienced solid economic performance in the past few years. This economic performance coupled with the recent increase in social public expenditures by the government has increased the likelihood that the country will achieve all of the MDGs by 2015, except probably for MDG 2. These advances have been achieved in a period of radical change in Bolivia's dependence on MDG8-related external flows. The composition of external finance in public expenditure has shifted from domination by ODA and debt forgiveness in the first half of the decade to domination by trade, mainly through revenues from hydrocarbon exports. Our findings support the idea that the provision of additional financial resources may not be the priority with regard to organising support to MDG achievements. Spending efficiently and effectively seems to be a more important area for support in Bolivia. As far as trade is concerned, Bolivia already enjoys good market access in its main markets, thus better access through lower non-tariff barriers may be more relevant than improving access in terms of tariffs. Moreover access to markets would be easier if Bolivia were better integrated with world markets, with its regional neighbours in particular. This calls for the support of the international community through aid for trade (AfT), which has instead been worryingly dwindling in recent years. Finally, we argue that MDG8 could be pursued in Bolivia through support for improving access to technology and access to affordable drugs

Ontology-Based Data Access and Integration

An ontology-based data integration (OBDI) system is an information management system consisting of three components: an ontology, a set of data sources, and the mapping between the two. The ontology is a conceptual, formal description of the domain of interest to a given organization (or a community of users), expressed in terms of relevant concepts, attributes of concepts, relationships between concepts, and logical assertions characterizing the domain knowledge. The data sources are the repositories accessible by the organization where data concerning the domain are stored. In the general case, such repositories are numerous, heterogeneous, each one managed and maintained independently from the others. The mapping is a precise specification of the correspondence between the data contained in the data sources and the elements of the ontology. The main purpose of an OBDI system is to allow information consumers to query the data using the elements in the ontology as predicates. In the special case where the organization manages a single data source, the term ontology-based data access (ODBA) system is used

Circuit Complexity Meets Ontology-Based Data Access

Ontology-based data access is an approach to organizing access to a database augmented with a logical theory. In this approach query answering proceeds through a reformulation of a given query into a new one which can be answered without any use of theory. Thus the problem reduces to the standard database setting. However, the size of the query may increase substantially during the reformulation. In this survey we review a recently developed framework on proving lower and upper bounds on the size of this reformulation by employing methods and results from Boolean circuit complexity.Comment: To appear in proceedings of CSR 2015, LNCS 9139, Springe

Dynamics of Manufacturing Competitiveness in South Asia: Analysis through Export Data

The outstanding export performance of South Asian countries (India in particular) over the 1990s has prompted some observers to see in it the roots of an export-led growth similar to that of its Southeast Asian neighbors. We employ export unit values (UVs) cum real competitiveness analysis to the manufacturing sector of four South Asian countries (with particular focus on India), in order to investigate the determinants of this apparent success. Shifts toward higher UVs relative to technology leaders serve as the most appropriate indication of underlying structural changes, and such change is manifested in technology closing-up processes among countries. According to our indices, the export competitiveness of South Asian countries (except Pakistan) seems to have slightly improved relative to its Southeast Asian comparators, but not relative to the Organisation for Economic Co-operation and Development. South Asian export growth has been mainly driven by relative quantity expansion through a reduction in relative costs rather than relative quality improvement. Such expansion has been concentrated in naturalresource-intensive, standard technology-intensive (in India), and labor-intensive sectors (in Bangladesh). On the other hand, the more technology-intensive sectors in India still suffer from a significant gap relative to Thailand that has not been closing up in the last decade. These findings suggest some notes of caution in interpreting the recent good export performance of South Asian economies

Ontology-based data access with databases: a short course

Ontology-based data access (OBDA) is regarded as a key ingredient of the new generation of information systems. In the OBDA paradigm, an ontology defines a high-level global schema of (already existing) data sources and provides a vocabulary for user queries. An OBDA system rewrites such queries and ontologies into the vocabulary of the data sources and then delegates the actual query evaluation to a suitable query answering system such as a relational database management system or a datalog engine. In this chapter, we mainly focus on OBDA with the ontology language OWL 2QL, one of the three profiles of the W3C standard Web Ontology Language OWL 2, and relational databases, although other possible languages will also be discussed. We consider different types of conjunctive query rewriting and their succinctness, different architectures of OBDA systems, and give an overview of the OBDA system Ontop

Flexible query processing for SPARQL

Flexible querying techniques can enhance users' access to complex, heterogeneous datasets in settings such as Linked Data, where the user may not always know how a query should be formulated in order to retrieve the desired answers. This paper presents query processing algorithms for a fragment of SPARQL 1.1 incorporating regular path queries (property path queries), extended with query approximation and relaxation operators. Our flexible query processing approach is based on query rewriting and returns answers incrementally according to their ``distance'' from the exact form of the query. We formally show the soundness, completeness and termination properties of our query rewriting algorithm. We also present empirical results that show promising query processing performance for the extended language