Centralized Versus Decentralized Detection of Attacks in Stochastic Interconnected Systems

We consider a security problem for interconnected systems governed by linear, discrete, time-invariant, stochastic dynamics, where the objective is to detect exogenous attacks by processing the measurements at different locations. We consider two classes of detectors, namely centralized and decentralized detectors, which differ primarily in their knowledge of the system model. In particular, a decentralized detector has a model of the dynamics of the isolated subsystems, but is unaware of the interconnection signals that are exchanged among subsystems. Instead, a centralized detector has a model of the entire dynamical system. We characterize the performance of the two detectors and show that, depending on the system and attack parameters, each of the detectors can outperform the other. In particular, it may be possible for the decentralized detector to outperform its centralized counterpart, despite having less information about the system dynamics, and this surprising property is due to the nature of the considered attack detection problem. To complement our results on the detection of attacks, we propose and solve an optimization problem to design attacks that maximally degrade the system performance while maintaining a pre-specified degree of detectability. Finally, we validate our findings via numerical studies on an electric power system.Comment: Submitted to IEEE Transactions on Automatic Control (TAC

Growth characteristics of Campylobacter sputorum subspecies mucosalis in cell cultures

In this study, the growth characteristics of Campylobacter sputorum ss mucosalis were investigated in twelve different types of cell cultures: primary cultures of porcine kidney (PPK), chicken embryo fibroblasts (CEF) and cell lines of porcine kidney (PK), bovine kidney (BK), canine kidney (DK), monkey kidney (Vero and LLCMK^)' baby hamster kidney (BHK-21), human cervical carcinoma (HeLa) cells and lines of porcine (PK ^), bovine (BK ^) and ovine (OK^) kidney cells persistently infected with Newcastle disease virus.As a prelude to infection of cell cultures prelim¬ inary studies on the morphology and ultrastructure of C. sputorum ss mucosalis and C. coli were undertaken. Negatively-stained preparations of serologically repre¬ sentative strains of mucosalis showed the presence of comma, S-shaped and long filamentous forms. Organisms were observed with three different surface coats: i) rough and scaly types with deep transverse clefts, ii) smooth types with longitudinal ridges and iii) smooth types without clefts or ridges. The production of these cell surface structures appeared to depend on the age of the culture and the type of growth medium used. Mucosalis organisms invariably possessed a single polar flagellusnand the flagellar appendage showed the presence of a 'collar-like® structure on either side of the filament at the site of attachment to the basal granule.In thin-sections, the presence of a double layered cell wall and cytoplasmic membrane were clearly visible, the cytoplasmic substance was granular and contained numerous polyphosphate crystals. By comparison, a strain of _C. coli showed coccoid or comma-shaped organisms with leathery cell surface with or without transverse clefts, however on section this organism closely re¬ sembled C. sputorum ss mucosalis except for the presence of a large cytoplasmic vacuole.C. sputorum ss mucosalis requires a hydrogen microaerophilic atmosphere for growth and maintenance, without which it becomes non-viable after 10-12 hr. Certain types of cell cultures can support 'parasitic growth' of this organism in the absence of such a hydrogen microaerophilic atmosphere. The evidence suggests that this 'cell dependant' growth is due to intracellular multiplication and release of bacteria from the infected cell cultures. In infected BK cells 'parasitic growth' of mucosalis can persist for up to 7 weeks.Investigations on the adhesive properties of mucosalis have shown that bacterial attachment is specific and is 'transitory', lasting upto 10-12 hr postinoculation. There appears to be a direct relationship between the ability of cell cultures to support 'parasitic growth' and to attach mucosalis organisms. The mechanisms involved in the adhesive process are complex although bacterial motility seems to enhance the attachment of mucosalis organisms. Bacterial cell surface structures, but not the flagella, are involved in the adhesive process to host-cell surface receptors.Infection of suspensions of trypsinized cells or preformed monolayers with C. sputorum ss mucosalis did not appear to interfere with the initial attachment and/or growth of infected cells, although characteristic cytopathic changes are found during later stages of infection. Electron microscopic studies show that following attachment to cell surfaces bacteria are engulfed by the infected cells and are later found in the phagosomes or free in the cytoplasmic substance. The intracellular fate of mucosalis organisms in the infected cell cultures depends on the type of cell infected. Pig kidney cells appear to destroy mucosalis organisms rapidly and characteristic bacteria disappear from the cytoplasm to be replaced by accumulations of granular material. In contrast, bovine kidney cells infected with mucosalis show, in addition to degenerate forms (ghost cells), morphologically normal bacteria. Com¬ prehensive evidence has been obtained, by viable counts of bacteria, light,immunofluorescent and electron microscopy, which strongly suggests that mucosalis is capable of intracellular multiplication, at least in the BK cell line.The response of different types of cell cultures to infection with mucosalis differs and can be broadly grouped as following:i. cell cultures that show 'parasitic growth' of mucosalis and rapid CPE with cell fusion and destruction of the infected monolayers. These include PPK, PK, and PK(pi) cells.ii. cell cultures that are less readily destroyed by mucosalis infection and give rise to the production of markedly enlarged 'altered cells', and limited cell fusion. Such cultures include BK, BK(pi) ., OK(pi) ., BHK and HeLa cells.iii. cell cultures including Vero and LLCNK₂ lines, that are 'initially' refractory to 'parasitic growth' and the production of CPE but which, on re-infection, behave like those in group (ii).iv. cell cultures that normally support 'parasitic growth' but fail to show any CPE, of which DK cells is an example.v. cell cultures that fail completely to support 'parasitic growth' and which do not show a CPE, even aft super-infection e.g. primary cultures of CEF.The experimental evidence indicates that the cellular abnormalities produced are associated with either the intracellular growth, or the presence of intracellular killed bacteria or bacterial products.The significance and future application of the findings of this work in relation to the pathogenesis of porcine intestinal adenomatosis, the disease associated with the presence of intracellular C. sputorum ss mucosalis, are discussed

Encopresis

This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of encopresis

The Economic Effects of Compulsory Medical Licensing

Over the past several decades, the United States has witnessed a rise in the demand for medical care, while the supply of doctors providing that care has remained flat. This paper traces the cause of that shortage to the compulsory licensing of physicians and examines alternative to that policy

Investigation of optical properties of InP, AIN and Sapphire for applications in non-contact semiconductor process monitoring

The objective of this thesis was to develop a reliable multi-wavelength pyrometer for simultaneous measurement of the wafer temperature and its optical properties in the wavelength range of 1 to 20 microns and temperature range of 30 to 1500° C. The spectral emissometer has been utilized for measurement of the temperature dependent optical properties of InP, AlN and Sapphire. The experimental results presented in this thesis showed that the measurement of high temperature optical properties could be performed reliably with a novel approach using the spectral ernissometer. The temperature determination capability of the emissometer was tested and verified using a standard thermocouple embedded in a silicon wafer. The temperature measurement accuracy, with the emissometer, was found to be within +/- 10° C of the thermocouple temperature for a temperature range of 30 to 300° C. A particularly interesting results were the observed sharp peak in the emissivity of Fe doped InP at 14 microns, the deconvoluted values of the refractive indices from the measured optical properties of Fe doped InP are within +/- 10 % of the limited refractive index data available in the literature, sapphire exhibiting emissivity value of ~1 at 8 microns and the refractive indices of sapphire approach high values in the wavelength range of 12 to 16 microns resulting from its high reflectance. Spectral emissometry has been established as a reliable technique for simultaneously measurement of temperature and optical properties of semiconductors

An intriguing autopsy case of gangrene intestine

Hypothyroidism, or myxedema, is the clinical syndrome that results from decreased production of T4 and T3.Most patients have primary hypothyroidism .The etiology of adult primary hypothyroidism includes autoimmune hypothyroidism (Hashimoto’s thyroiditis), post – ablation after radio-active iodine, thyroid surgery and drugs such as Amiodarone and Lithium. Manifestations are variable and proportionate to the degree and duration of thyroid hormone deficiency as well as age of onset. The presence of goiter is common in younger patients (Hashimoto’s) but often absent in the elderly. Clinical features of hypothyroidism are insidious and often missed, particularly in the elderly

Evaluation of methods for measuring aggregate specific gravity

The current American Association of State Highway and Transportation Officials (AASHTO) procedures for determining the aggregate specific gravities and absorption values are time consuming and hence are not appropriate for quality control processes. These methods are not repeatable too which is another issue with the standard test methods. The standard AASHTO method for fine aggregates has problems with angular and absorptive materials. Due to this problem several agencies have developed alternative methods. Correct measurement of the specific gravity and absorption play a crucial role in the design of hot mix asphalt (HMA) mixtures. Improper measurements can lead to poor asphalt being accepted for a certain job and on the other hand good quality asphalt may be rejected. The pavement life is at great risk if poor quality asphalt is accepted. And there can be a lot of cost concerns if good quality asphalt is being rejected.;This research evaluated the specific gravity test methods for fine aggregates. The focus of the research is to find a test method that is suitable for all types of fine aggregates. There were 9 different methods used to determine the fine aggregate specific gravities apart from the standard AASHTO method. All the selected methods are the modifications made by other agencies in order to improve the test accuracy. The comparison between the different methods to the AASHTO method was done using the student t distribution test

Integration of Java EE Applications on C – Based Implementations

Sometimes we may encounter a scenario in which  We need to Integrate the existing Java – Based applications  With the Native formats of C/C++ Based implementations  For example the applications of Defense, Aerospace weather Forecasting Applications contain complex algorithms and that might be too complex  And too difficult or even some times implementing those again will include risqué as well As time consuming also in such cases to integrate such C based implementations with java programs We need an adapter in between those two  language API ‘s . The Java Native Interface (JNI) will provide you the bridge for exchanging data between java and C,C++ API’s this article describes the steps that will ease the integration of JAVA With C- Based  Implementations. Keywords: JNI : Java Native Interface API : Application Programming Interfac