Linux kernel compaction through cold code swapping

There is a growing trend to use general-purpose operating systems like Linux in embedded systems. Previous research focused on using compaction and specialization techniques to adapt a general-purpose OS to the memory-constrained environment, presented by most, embedded systems. However, there is still room for improvement: it has been shown that even after application of the aforementioned techniques more than 50% of the kernel code remains unexecuted under normal system operation. We introduce a new technique that reduces the Linux kernel code memory footprint, through on-demand code loading of infrequently executed code, for systems that support virtual memory. In this paper, we describe our general approach, and we study code placement algorithms to minimize the performance impact of the code loading. A code, size reduction of 68% is achieved, with a 2.2% execution speedup of the system-mode execution time, for a case study based on the MediaBench II benchmark suite

The Importance of Audit Firm Characteristics and the Drivers of Auditor Change in UK Listed Companies

This paper explores the importance of audit firm characteristics and the factors motivating auditor change based on questionnaire responses from 210 listed UK companies (a response rate of 70%). Twenty-nine potentially desirable auditor characteristics are identified from the extant literature and their importance elicited. Exploratory factor analysis reduces these variables to eight uncorrelated underlying dimensions: reputation/quality; acceptability to third parties; value for money; ability to provide non-audit services; small audit firm; specialist industry knowledge; non-Big Six large audit firm; and geographical proximity. Insights into the nature of 'the Big Six factor' emerge. Two thirds of companies had recently considered changing auditors; the main reasons cited being audit fee level, dissatisfaction with audit quality and changes in top management. Of those companies that considered change, 73% did not actually do so, the main reasons cited being fee reduction by the incumbent and avoidance of disruption. Thus audit fee levels are both a key precipitator of change and a key factor in retaining the status quo

The impact of constructive operating lease capitalisation on key accounting ratios

Current UK lease accounting regulation does not require operating leases to be capitalised in the accounts of lessees, although this is likely to change with the publication of FRS 5. This study conducts a prospective analysis of the effects of such a change. The potential magnitude of the impact of lease capitalisation upon individual users' decisions, market valuations, company cash flows, and managers' behaviour can be indicated by the effect on key accounting ratios, which are employed in decision-making and in financial contracts. The capitalised value of operating leases is estimated using a method similar to that suggested by Imhoff, Lipe and Wright (1991), adapted for the UK accounting and tax environment, and developed to incorporate company-specific assumptions. Results for 1994 for a random sample of 300 listed UK companies show that, on average, the unrecorded long-term liability represented 39% of reported long-term debt, while the unrecorded asset represented 6% of total assets. Capitalisation had a significant impact (at the 1% level) on six of the nine selected ratios (profit margin, return on assets, asset turnover, and three measures of gearing). Moreover, the Spearman rank correlation between each ratio before and after capitalisation revealed that the ranking of companies changed markedly for gearing measures in particular. There were significant inter-industry variations, with the services sector experiencing the greatest impact. An analysis of the impact of capitalisation over the five-year period from 1990 to 1994 showed that capitalisation had the greatest impact during the trough of the recession. Results were shown to be robust with respect to key assumptions of the capitalisation method. These findings contribute to the assessment of the economic consequences of a policy change requiring operating lease capitalisation. Significant changes in the magnitude of key accounting ratios and a major shift in company performance rankings suggest that interested parties' decisions and company cash flows are likely to be affected

Cloaked Facebook pages: Exploring fake Islamist propaganda in social media

This research analyses cloaked Facebook pages that are created to spread political propaganda by cloaking a user profile and imitating the identity of a political opponent in order to spark hateful and aggressive reactions. This inquiry is pursued through a multi-sited online ethnographic case study of Danish Facebook pages disguised as radical Islamist pages, which provoked racist and anti-Muslim reactions as well as negative sentiments towards refugees and immigrants in Denmark in general. Drawing on Jessie Daniels’ critical insights into cloaked websites, this research furthermore analyses the epistemological, methodological and conceptual challenges of online propaganda. It enhances our understanding of disinformation and propaganda in an increasingly interactive social media environment and contributes to a critical inquiry into social media and subversive politics

Relative abundance of organochlorine pesticides and polychlorinated biphenyls in adipose tissue and serum of women

Some organochlorine pesticides (OCPs) and PCBs are under investigation as possible risk factors for breast cancer because of their estrogenic properties and widespread presence in the environment. It is important to know whether adipose tissue used by some investigators and serum assays used by others can provide comparable information on body burden. Concentrations of seven OCPs or their breakdown products as well as 14 PCB congeners were measured in the adipose tissue and serum of 293 women enrolled as controls in a case-control study of environmental factors for breast cancer in Long Island, New York, a high-risk region. Adipose OCP/PCB levels were measured using a supercritical fluid extraction method developed by the authors. 1,1-Dichloro-2,2-di(4-chlorophenyl)ethylene (p,p’- DDE) was detected in all adipose and serum samples; two chlordane derivatives, β-hexachlorocyclohexane (a lindane isomer) and hexachlorobenzene, were detected in at least 92% of adipose samples. The di-ortho hexachlorinated PCB congeners 2,4,5,2’,4’,5’- hexachlorobiphenyl and 2,3,4,2’,4’,5’-hexachlorobiphenyl were detected in all adipose and over 98% of serum samples. 1,1-Dichloro-2,2-di(4-chlorophenyl)ethylene comprised 77% of total pesticide residues in adipose and 71% in serum. 2,4,5,2’,4’,5’-Hexachlorobiphenyl comprised 24% of adipose and 21 % of serum PCBs. The relative concentration patterns of the 14 PCB congeners were similar to those reported in other human studies and were also typical of patterns reported in environmental samples from various biota, including mammals and birds, but differed substantially from patterns reported in occupationally exposed workers. All adipose-serum correlations for pesticides and most PCBs were statistically significant. Either serum or adipose OCP/PCB levels of a variety of environmental organochlorine compounds may serve as useful biomarkers of body burden

Feasibility and Cardiac Safety of Trastuzumab Emtansine After Anthracycline-Based Chemotherapy As (neo) Adjuvant Therapy for Human Epidermal Growth Factor Receptor 2-Positive Early-Stage Breast Cancer

Purpose Trastuzumab emtansine (T-DM1), an antibody-drug conjugate comprising the cytotoxic agent DM1, a stable linker, and trastuzumab, has demonstrated substantial activity in human epidermal growth factor receptor 2 (HER2) -positive metastatic breast cancer, raising interest in evaluating the feasibility and cardiac safety of T-DM1 in early-stage breast cancer (EBC). Patients and Methods Patients (N = 153) with HER2-positive EBC and prechemotherapy left ventricular ejection fraction (LVEF) \u3e= 55% received (neo) adjuvant doxorubicin plus cyclophosphamide or fluorouracil plus epirubicin plus cyclophosphamide followed by T-DM1 for four cycles. Patients could then receive three to four cycles of optional docetaxel with or without trastuzumab. T-DM1 was then resumed with optional radiotherapy (sequential or concurrent) for 1 year (planned) of HER2-directed therapy. The coprimary end points were rate of prespecified cardiac events and safety. Results Median follow-up was 24.6 months. No prespecified cardiac events or symptomatic congestive heart failures were reported. Four patients (2.7%) had asymptomatic LVEF declines (\u3e= 10 percentage points from baseline to LVEF\u3c 50%), leading to T-DM1 discontinuation in one patient. Of 148 patients who received \u3e= one cycle of T-DM1, 82.4% completed the planned 1-year duration of HER2-directed therapy. During T-DM1 treatment, 38.5% and 2.7% of patients experienced grade 3 and 4 adverse events, respectively. Approximately 95% of patients receiving T-DM1 plus radiotherapy completed \u3e= 95% of the planned radiation dose with dela

Evaluation and Improvement of Control Vector Iteration Procedures for Optimal Control

An alternate graphical representation of linear, time-invariant, multi-input, multi-output (MIMO) system dynamics is proposed that is highly suited for exploring the influence of closedloop system parameters. The development is based on the adjustment of a scalar forward gain multiplying a cascaded multivariable controller/plant embedded in an output feedback configuration. By tracking the closed-loop eigenvalues as explicit functions of gain, it is possible to visualize the multivariable root loci in a set of "gain plots" consisting of two graphs: (i) magnitude of system eigenvalues versus gain and (ii) argument (angle) of system eigenvalues versus gain. The gain plots offer an alternative perspective of the standard MIMO root locus plot by depicting unambiguously the polar coordinates of each eigenvalue in the complex plane. Two example problems demonstrate the utility of gain plots for interpreting closed-loop multivariable system behavior. Introduction Since their introduction, classical control tools have been popular for analysis and design of single-input, single-output (SISO) systems. These tools may be viewed as specialized versions of more general methods that are applicable to multiinput, multi-output (MIMO) systems. Although modern "statespace" control techniques (relying on dynamic models of internal structure) are generally promoted as the predominant tools for multivariable system analysis, the classical control extensions offer several advantages, including requiring only an input-output map and providing direct insight into stability, performance, and robustness of MIMO systems. The understanding generated by these graphically based methods for the analysis and design of MIMO systems is a prime motivator of this research. An early graphical method for investigating the stability of linear, time-invariant (LTI) SISO systems was developed by ference transfer function matrix ([I + G(s)] where G(s) is the open-loop system transfer function matrix, rather than just 1 + g(s) for the SISO case where g{s) is the system transfer function). Despite the complication, significant research has supported the MIMO Nyquist extension for assessment of multivariable system stability and robustness The Bode plots Although promoted as an SISO tool, Evans root locus method To aid the controls engineer in extracting more information from the multivariable Evans root locus plot, we propose a set of "gain plots" that provide a direct and unique window into the stability, performance, and robustness of LTI MIMO systems. A conceptual framework motivating the gain plots and a discussion of their applicability to SISO systems has been presented previously Multivariable Eigenvalue Description Basic MIMO Concepts. A LTI MIMO plant can be represented in the standard state-space form as where state vector x p is length n, input vector u is length m, and output vector y is length m. Matrices A p , B p , C p , and D p are the system matrix, the control influence matrix, the output matrix, and the feed-forward matrix, respectively, of the plant with appropriate dimensions. The plant input-output dynamics are governed by the transfer function matrix, G p (s), GpW^CplsI-ApV'Bp + Vp (3) The system is embedded in the closed-loop configuration shown in Fig. 1 Ml MO closed-loop negative feedback configuration where A c , B c , C c , and D c are the controller matrices representing its internal structure, in similarity to Eqs. In the MIMO root locus plot, the migration of the eigenvalues of G*(5) in the complex plane is graphed for 0 < k < oo. (By equating the determinant of [I + kG p (s)G c (s)] to zero, the MIMO generalization of the SISO characteristic equation The presence of the determinant is the major challenge in generalizing the SISO root locus sketching rules to MIMO systems and complicates the root locus plot.) The closed-loop system dynamics can alternatively be cast in state-space form in terms of state vector r . The closed-loop system matrix then becomes where The eigenvalues of the closed-loop system,5 = X; = eig(A') (i = 1,2, . . . , «), may be computed numerically from Eq. (6). In the examples, the loci of the eigenvalues are calculated as k is monotonically increased from zero. High Gain Behavior. As the gain is swept from zero to infinity, the closed-loop eigenvalues trace out "root loci" in the complex plane. At zero gain, the poles of the closed-loop system are the open-loop eigenvalues. At infinite gain some of the eigenvalues approach finite transmission zeros, defined to be those values of s that satisfy the generalized eigenvalue problem. In the absence of pole/zero cancellation, the finite transmission zeros are the roots of the determinants of G p (s) and G c (s). Algorithms have been developed for efficient and accurate computation of transmission zeros The eigenvalues can be considered as always migrating from the open-loop poles to their matching transmission zeros MIMO Gain Plots. Just as the Bode plots embellish the information of the Nyquist diagram by exposing frequency explicitly in a set of magnitude versus frequency and angle (phase) versus frequency plots, it follows that a pair of gain plots (Kurfess and Nagurka, 1991) can enhance the standard root locus plot. As the gain-domain analog of the frequencydomain Bode plots, the gain plots explicitly depict the eigenvalue magnitude versus gain in a magnitude gain plot, and the eigenvalue angle versus gain in an angle gain plot. In similarity to the Bode plots, the magnitude gain plot employs a log-log scale whereas the angle gain plot uses a semi-log scale (with the logarithms being base 10). Although gain is selected as the variable of interest in the gain plots, it should be noted that any scalar parameter may be used in the geometric analysis, leading to the more generic idea of parametric plots. Gain plots can be drawn for both SISO and MIMO systems. In MIMO systems it is assumed that a single scalar gain amplifies all controller/plant inputs. For such systems, inspection of the magnitude and angle gain plots enables one to uniquely identify locus branches as a function of gain. As such, gain plots are a natural complement to multivariable root locus plots, where uncharacteristically confusing eigenvalue trajectories can result from being drawn in a single complex plane. Furthermore, it can be shown that the slopes of the lines in the gain plots are proportionally related to the root sensitivity function (Kurfess and Nagurka, 1992). MIMO Examples This section presents two multivariable examples. The first example introduces the concept of the gain plots and demonstrates the insight they offer by "unwrapping" the multivariable root locus and exposing unambiguous behavior. The second example highlights the power of the gain plots in revealing typical multivariable properties, such as high gain Butterworth patterns. Example 1: Coupled MIMO Example. The forward loop dynamics of this example are given by the transfer function matrix (Equation The gain plots presented in The gain plots highlight several other important features. For example, they show that the gains corresponding to the complex conjugate eigenvalue pairs break into the real axis and then proceed toward ± oo. Complex conjugate eigenvalues are shown as symmetric lines about either the 180 or 0 deg line with equal magnitudes. Purely real eigenvalues possess equal angles (180 or 0 deg) but distinct magnitudes. This behavior is demonstrated in The rates at which the eigenvalues increase toward infinite magnitude is seen in the magnitude gain plot of From Conclusions In typical MIMO root locus plots trajectories may be camouflaged as branches may overlap. Gain plots are promoted as a means to "untangle" MIMO eigenvalue trajectories. The major enhancement is the visualization of eigenvalue trajectories as an explicit function of gain, assumed here to be the same static gain applied to all error signals. The perspective presented in this note is intended to complement the many tools available to the controls engineer. In particular, for MIMO systems the gain plots provide: (/) a unique description of eigenvalues and their trajectories as a parameter, such as gain, is varied, (ii) a geometric depiction of the Riemann sheets at high gain, and (Hi) a rich educational tool for conducting parametric analyses of multivariable systems. Research efforts, currently underway, may shed additional light on gain plots for multivariable systems. In addition, work by MacFarlane and'Postlethwaite (1977 and In conclusion, gain plots enrich the multivarible root locus plot in much the same way that singular value frequency plots are an alternate and extended presentation of the multivariable Nyquist diagram. Their use in conjunction with the multivariable root locus provides a valuable geometric perspective on multivariable system behavior. Acknowledgment The authors wish to thank Mr. Ssu-Kuei Wang for his help, and for his earnest enthusiasm of gain plots for studying multivariable and optimal systems

Body Mass Index, PAM50 Subtype, and Outcomes in Node-Positive Breast Cancer: CALGB 9741 (Alliance)

BACKGROUND: Obesity at diagnosis is associated with poor prognosis in women with breast cancer, but few reports have been adjusted for treatment factors. METHODS: CALGB 9741 was a randomized trial of dose density and sequence of chemotherapy for node-positive breast cancer. All patients received doxorubicin, cyclophosphamide, and paclitaxel, dosed by actual body weight. Height and weight at diagnosis were abstracted from patient records, and the PAM50 assay was performed from archived specimens using the NanoString platform. Relationships between body mass index (BMI), PAM50, and recurrence-free and overall survival (RFS and OS) were evaluated using proportional hazards regression, adjusting for number of involved nodes, estrogen receptor (ER) status, tumor size, menopausal status, drug sequence, and dose density. All statistical tests were two-sided. RESULTS: Baseline height and weight were available for 1909 of 2005 enrolled patients; 1272 additionally had subtype determination by PAM50. Median baseline BMI was 27.4kg/m(2). After 11 years of median follow-up, there were 619 RFS events and 543 deaths. Baseline BMI was a statistically significant predictor of RFS (adjusted hazard ratio [HR] for each five-unit increase in BMI = 1.08, 95% confidence interval [CI] = 1.02 to 1.14, P = .01) and OS (adjusted HR = 1.08, 95% CI = 1.01 to 1.14, P = .02) BMI and molecular phenotypes were independent prognostic factors for RFS, with no statistically significant interactions detected. CONCLUSIONS: BMI at diagnosis was a statistically significant prognostic factor in a group of patients receiving optimally dosed chemotherapy. Additional research is needed to determine the impact of weight loss on breast cancer outcomes and to evaluate whether this impact is maintained across tumor subtypes