My model-theoretic realist account of science places linguistic systems and the corresponding non-linguistic structures at different stages of the scientific process. It is shown that science and its progress cannot be analysed in terms of only one of these strata. Philosophy of science literature offers mainly two approaches to the structure of scientific knowledge analysed in terms of theories and their models, the "statement" and the "non-statement" approaches. In opposition to the statement approach's belief that scientific knowledge is embodied in theories (formulated in some (first-order) symbolic language) with direct interpretative links - via so-called "bridge principles" - to reality, the defenders of the non-statement approach believe in an analysis where the language in which the theory is formulated plays a much smaller role than the (mathematical) structures which satisfy that theory. The model-theoretic realism expounded here retains the notion of a scientific theory as a (deductively closed) set of sentences, while simultaneously emphasising the interpretative role of the conceptual (i.a. mathematical) models of these theories. My criticism against the non-statement approach is based on the fact that merely "giving" the theory "in terms of' its mathematical structures leaves out any real interpretation of the nature and role of general terms in science. Against the statement approach's "direct" linking of general theoretical terms to reality, my approach interpolates models between theories and (aspects of) reality in the interpretative chain. The links between the general terms of scientific theories and their interpretations in the various models of the theory regulate the whole referential process. The terms of a theory are "general" in the sense that they are the result of certain abstractive conceptualisations of the object of scientific investigation and subsequent linguistic formulations of these conceptualisations. Their (particular) meanings can be "given back" only by interpreting them in the limited context of the various conceptual models of their theory and, finally, by finding an isomorphic relation between some substructure of the conceptual model in question and some empirical conceptualisation (model) of relevant experimental data. In this sense the notion of scientific "truth" becomes inextricably linked with that of articulated reference, as it - given its model-dependent nature - should be. / Philosophy, Practical & Systematic Theology / D.Litt. et Phil. (Philosophy)

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / In this paper, we present a methodology for managing diverse sources of T&E metadata. Central to this methodology is the development of a T&E Metadata Reference Model, which serves as the standard model for T&E metadata types, their proper names, and their relationships to each other. We describe how this reference model can be mapped to a range's own T&E data and process models to provide a standardized view into each organization's custom metadata sources and procedures. Finally, we present an architecture that uses these models and mappings to support cross-system metadata management tasks and makes these capabilities accessible across the network through a single portal interface.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper briefly reports on concepts for hardening (physically toughening) crystal reference oscillators for the highly integrated program known as HSTSS. Within the HSTSS program is the L & S band transmitter development contract. The harshest requirements for this contract are surviving and functioning, to within 20 ppm of its center frequency, 30 ms after sustaining a shock pulse of 100,000 (g) for 0.5 ms on any axis. Additional requirements call for the transmitter to be no larger than 0.2 in3, and to operate within a 20 ppm frequency stability throughout the temperature range of -400 to +850 centigrade and during centrifugal spins of up to 300 Hz or 25,000 (g). Fundamentally the question is, is it feasible for any telemetry system to be capable of withstanding such harsh conditions and, to be practical on all DoD Test Ranges, still adhere to the stability tolerance guidelines set forth by the Range Commanders Council on Telemetry Standards - IRIG 106-96? Under "normal" conditions, stability requirements for "Range" transmitters are easily satisfied through the use of off-the-shelf crystal reference oscillators which provide the reference frequencies required within a transmitter’s phase lock loop circuitry. Unfortunately, the oscillator is also the most vulnerable part of a transmitter to the conditions listed and is the key to this problem. The oscillator’s weak points are in its resonator’s fragile quartz structure (the blank) and support mechanism. The challenge is to invent and adapt this area to these newer harsher conditions and to do it in the smallest space ever required.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes a kind of Microwave Digital Frequency Synthesizer used for S-band telemetry receivers. As well known many modern electronic systems employ a Frequency Synthesizer whose spectral purity is critical. The characteristics of a PLL (Phase-Locked Loop) Frequency Synthesizer, such as frequency resolution, phase noise, spurious suppression and switch time, should be compromised in our design. A heterodyne Frequency Synthesis is often considered as a good approach to solve the problem. But it is complicated in structure and circuit. A variable-reference-driven PLL Frequency Synthesizer was introduced which can give an improved trade-off among frequency resolution, phase noise, spurious suppression. In this paper the phase noise and spurious suppression characteristic of variable-reference-driven PLL Frequency Synthesizer is analyzed theoretically and compared with that of the heterodyne Frequency Synthesizer. For engineering application, a practical Microwave Digital Frequency Synthesizer used for telemetry receiver has been designed, which is characterized by simply structure, low phase noise and low spurious output. The output spectrum of experimental measurements is given.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The 746th Test Squadron at Holloman AFB has developed and utilized the Central Inertial Guidance Test Facility (CIGTF) High Accuracy Post-processing Reference System (CHAPS). CHAPS is a multi-sensor navigation reference system used to evaluate position, velocity, and attitude performance of Global Positioning System (GPS), Inertial Navigation System (INS), and Embedded GPS/INS (EGI) navigation systems on large vehicles and aircraft. Reference data is processed post-test with accuracy ranges from a meter to sub-meter depending on the reference configuration and test environment (profile, trajectory dynamics, GPS jamming, etc.). The GPS Aided Inertial Navigation Reference (GAINR) system developed by the Air Force Flight Test Center (Edwards AFB) offered other utilization capabilities (test beds and post-processing time). The basic sensor assembly is an EGI navigation system. The data are post-processed with Multisensor Optimal Smoothing Estimation Software (MOSES). Incorporating CHAPS and GAINR capabilities generates a reference system with enhanced accuracy (sub-meter) in a dynamic GPS non-jamming/jamming environment. This paper will present the enhanced reference system combination of CHAPS/GAINR capabilities, characterization process and development methodology.

The author presents an analysis of how speakers establish references in conversation. Further, this paper focuses on what words of a reference are conventionalized as speakers coordinate multiple times. The author explores how the co-occurrence of the reference terms with the referent can be a good predictor of what words are conventionalized over time. In order to study this, the author created an online version of the reference game from Clark and Wilkes-Gibbs (1986) experiment, where a matcher and director must describe a set of ambiguous shapes to each other many times. By creating an online version of this reference game the author was able to gather significantly more data and analyze the data with computational tools. Results prove that co-occurrence is a useful predictor of terms which are conventionalized, providing a first step for accounting for statistical inference in the process of conventionalization.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / The telemetry industry must take advantage of the constantly increasing capability and decreasing per unit costs of network technology. The most effective way to do this is to adopt the layered reference model approach that is being used throughout the telecommunications industry. With a layered reference model, the interfaces between the layers are defined. As a layer is changed, the new layer must adhere to the same interfaces as the previous one. This approach easily allows new technology insertion in key areas without affecting the rest of the system. The Navy and the Air Force see this approach as a key component of acquisition reform and have established a comprehensive road map to achieve this goal.

published_or_final_version / abstract / Speech and Hearing Sciences / Doctoral / Doctor of Philosophy

Due to wealth of advantages offered by short range ultra wideband (UWB) technology, such as capacity improvement, fading reduction and localization, it has gathered a considerable attention. Distinct UWB qualities also pose many system design challenges like difficulties in using digital processing, complex channel estimation and different propagation characteristics. The main objective of the thesis is to develop and evaluate efficient modulation and detection schemes for impulse radio (IR) UWB with a focus on wireless sensor networks characterized by low cost and low power consumption. The content of the thesis comprises of five parts. In Part I, a coherent RAKE and non-coherent energy detector (ED) and transmitted reference (TR) receivers are examined and their bit-error-rate (BER) performance is evaluated using channels measured in an industrial environment. In specific, selective RAKE (SRake) and partial RAKE (PRake) for both maximal ratio combining (MRC) and equal gain combining (EGC) are compared. Based on the analysis and simulation results, it is concluded the SRake with EGC is to be preferred, whereas the best complexity/performance trade-off is provided by the ED based receivers. Part II presents several signaling and detection schemes; the proposed schemes are recursive TR (R-TR), dual-doublet TR (DDTR), doublet-shift TR (DSTR) and binary pulse position modulation (BPPM)/DSTR. Analysis and simulations verify that the proposed schemes may be preferred over the conventional TR in terms of BER, energy efficiency and/or implementation complexity. Part III presents a non-coherent kurtosis detector (KD) and a fourth-order detector (FD), which can discriminate between Gaussian noise and non-Gaussian IR-UWB signals by directly estimating the fourth-order moment of the received signal. Empirical evaluations and simulations using channel measurements conducted in a corridor, an office and a laboratory environment verify that performance of the proposed FD receiver is slightly better than the ED in the low SNR region and its performance improves as the SNR increases. Part IV presents a robust weighted ED (WED) in which the weighting coefficients are estimated adaptively based on the received stochastic data. Simulation results confirm that performance of the proposed weight estimation method is close to that of a data-aided (DA) scheme. Finally, Part V focuses on a multi-user scenario and develops a weighted code-multiplexed TR (WCM-TR) receiver employing the robust adaptive weight estimation scheme. Secondly, a BPPM/CM-TR UWB system is presented to mitigate inter-frame interference (IFI) and multi-user interference (MUI) from other asynchronous users. The BPPM/CM-TR system is 3 dB energy-efficient and improves the BER performance by mitigating MUI/IFI in the high SNR region, while for the low SNR case and single-user scenario, a dual-mode BPPM/CM-TR system is suggested

The thesis underpinning this study is as follows; it is possible to build machine models that are indistinguishable from the mental models used by humans to generate language to describe their environment. This is to say that the machine model should perform in such a way that a human listener could not discern whether a description of a scene was generated by a human or by the machine model. Many linguistic processes are used to generate even simple scene descriptions and developing machine models of all of them is beyond the scope of this study. The goal of this study is, therefore, to model a sufficient part of the scene description process, operating in a sufficiently realistic environment, so that the likelihood of being able to build machine models of the remaining processes, operating in the real world, can be established. The relatively under-researched process of reference object selection is chosen as the focus of this study. A reference object is, for instance, the `table' in the phrase ``The flowers are on the table''. This study demonstrates that the reference selection process is of similar complexity to others involved in generating scene descriptions which include: assigning prepositions, selecting reference frames and disambiguating objects (usually termed `generating referring expressions'). The secondary thesis of this study is therefore; it is possible to build a machine model that is indistinguishable from the mental models used by humans in selecting reference objects. Most of the practical work in the study is aimed at establishing this. An environment sufficiently near to the real-world for the machine models to operate on is developed as part of this study. It consists of a series of 3-dimensional scenes containing multiple objects that are recognisable to humans and `readable' by the machine models. The rationale for this approach is discussed. The performance of human subjects in describing this environment is evaluated, and measures by which the human performance can be compared to the performance of the machine models are discussed. The machine models used in the study are variants on Bayesian networks. A new approach to learning the structure of a subset of Bayesian networks is presented. Simple existing Bayesian classifiers such as naive or tree augmented naive networks did not perform sufficiently well. A significant result of this study is that useful machine models for reference object choice are of such complexity that a machine learning approach is required. Earlier proposals based on sum-of weighted-factors or similar constructions will not produce satisfactory models. Two differently derived sets of variables are used and compared in this study. Firstly variables derived from the basic geometry of the scene and the properties of objects are used. Models built from these variables match the choice of reference of a group of humans some 73\% of the time, as compared with 90\% for the median human subject. Secondly variables derived from `ray casting' the scene are used. Ray cast variables performed much worse than anticipated, suggesting that humans use object knowledge as well as immediate perception in the reference choice task. Models combining geometric and ray-cast variables match the choice of reference of the group of humans some 76\% of the time. Although niether of these machine models are likely to be indistinguishable from a human, the reference choices are rarely, if ever, entirely ridiculous. A secondary goal of the study is to contribute to the understanding of the process by which humans select reference objects. Several statistically significant results concerning the necessary complexity of the human models and the nature of the variables within them are established. Problems that remain with both the representation of the near-real-world environment and the Bayesian models and variables used within them are detailed. While these problems cast some doubt on the results it is argued that solving these problems is possible and would, on balance, lead to improved performance of the machine models. This further supports the assertion that machine models producing reference choices indistinguishable from those of humans are possible.