Performance Analysis of Industrial Cooperative Communication System in Generalized Fading Environment

This paper considers the performance analysis of M-ary phase shift keying industrial cooperative relaying system in Nakagami-m multipath fading channel with Gamma shadowing, which is known as the Generalized-K composite fading channel. Since the paper deals with the industrial environment, the communication channel is also affected by the additive Middleton\u27s Class-A impulsive noise. The bit error rate is used as a performance measure and the closed-form average bit error rate expression was derived. The influence of different fading and noise parameters on the system performance is investigated. The obtained results may be used for the improvement of the present and future industrial wireless communication systems

PERFORMANCE ANALYSIS OF DUAL-BRANCH SELECTION DIVERSITY SYSTEM USING NOVEL MATHEMATICAL APPROACH

In this paper, novel mathematical approach for evaluation of probability density function (PDF) of instantaneous signal-to-interference ratio (SIR) at the receiver output in interference-limited environment is proposed. Dual-branch selection combining (SC) receiver operating over correlated Weibull fading channels applying SIR algorithm is considered. Analytical expression for joint PDF of desired signal and interference at the receiver output is derived and used for evaluation of PDF of instantaneous SIR. The expression for PDF of SIR is used for system performance analysis via outage probability, average bit error probability (ABEP) and average output SIR as system performance measures. Numerical results are graphically presented showing the effects of fading severity, average SIR at the input and level of correlation on the diversity receiver performance. In addition, results obtained for the PDF of instantaneous SIR in this paper, are compared to the results when the PDF of instantaneous SIR is directly calculated

Performance analysis of dual-branch selection diversity receiver that uses desired signal algorithm in correlated Weibull fading environment

Rad je usmjeren na analizu karakteristika višestrukog sustava selektivnog kombiniranja (SC) s dvije grane gdje su i interferencija željenog signala i ko-kanalna interferencija (CCI) izložene Weibull fedingu. Za slučaj kada se algoritam željenog signala rabi kao kriterij za donošenje odluke izvedeni su izrazi zatvorenog oblika za zajedničku funkciju raspodjele vjerojatnosti (PDF) željenog signala i interferencije kao i PDF za trenutačni odnos signal-interferencija (SIR) na izlazu sustava. Ovi se izrazi rabe za analizu karakteristika cijeloga sustava rabeći vjerojatnost otkaza sustava, prosječnu vjerojatnost greške bita (ABEP) i prosječni izlaz SIR kao mjere za karakteristike sustava. Konačno, rezultati dobiveni u ovom radu uspoređeni su s ranije objavljenim rezultatima za isti sustav koji rabi algoritam na bazi SIR-a.This paper focuses on performance analysis of dual-branch selection combining (SC) diversity system where both, desired signal as well as co-channel interference (CCI), are subjected to Weibull fading. For the case when desired signal algorithm is used as decision criterion, closed form expressions for joint probability density function (PDF) of desired signal and interference as well as PDF for instantaneous signal-to-interference ratio (SIR) at the system output are derived. These expressions are used for overall system performance analysis using outage probability, average bit error probability (ABEP) and average output SIR as system performance measures. Finally, the results obtained in this paper are compared to the previously published results for the same system that uses SIR based algorithm

Performance analysis of dual-branch selection diversity receiver that uses desired signal algorithm in correlated Weibull fading environment

Rad je usmjeren na analizu karakteristika višestrukog sustava selektivnog kombiniranja (SC) s dvije grane gdje su i interferencija željenog signala i ko-kanalna interferencija (CCI) izložene Weibull fedingu. Za slučaj kada se algoritam željenog signala rabi kao kriterij za donošenje odluke izvedeni su izrazi zatvorenog oblika za zajedničku funkciju raspodjele vjerojatnosti (PDF) željenog signala i interferencije kao i PDF za trenutačni odnos signal-interferencija (SIR) na izlazu sustava. Ovi se izrazi rabe za analizu karakteristika cijeloga sustava rabeći vjerojatnost otkaza sustava, prosječnu vjerojatnost greške bita (ABEP) i prosječni izlaz SIR kao mjere za karakteristike sustava. Konačno, rezultati dobiveni u ovom radu uspoređeni su s ranije objavljenim rezultatima za isti sustav koji rabi algoritam na bazi SIR-a.This paper focuses on performance analysis of dual-branch selection combining (SC) diversity system where both, desired signal as well as co-channel interference (CCI), are subjected to Weibull fading. For the case when desired signal algorithm is used as decision criterion, closed form expressions for joint probability density function (PDF) of desired signal and interference as well as PDF for instantaneous signal-to-interference ratio (SIR) at the system output are derived. These expressions are used for overall system performance analysis using outage probability, average bit error probability (ABEP) and average output SIR as system performance measures. Finally, the results obtained in this paper are compared to the previously published results for the same system that uses SIR based algorithm

PERFORMANCE OF MACRO DIVERSITY WIRELESS COMMUNICATION SYSTEM OPERATING IN WEIBUL MULTIPATH FADING ENVIRONMENT

In this paper, we consider wireless mobile radio communication system with macro diversity reception. Signal is subject to Weibull small scale fading and Gamma large scale fading resulting in system performance degradation. Receiver uses macro diversity selection combining (SC) technique in order to reduce the impact of long term fading effects, and two micro diversity SC branches are used to mitigate Weibull short term fading effects on system performance. Probability density function (PDF), and cumulative distribution function (CDF), as well as level crossing rate (LCR) and average fade duration (AFD) of the SC receiver output signal envelope are evaluated. The obtained expressions converge rapidly for all considered values of Weibull fading parameter and Gamma shadowing severity parameter. Mathematical results are studied in order to analyze the influence of Weibull fading parameter and Gamma shadowing severity parameter on statistical properties of the SC receiver output signal

CHANNEL CAPACITY OF THE MACRO-DIVERSITY SC SYSTEM IN THE PRESENCE OF KAPPA-MU FADING AND CORRELATED SLOW GAMMA FADING

In this paper macrodiversity system consisting of two microdiversity SC (Selection Combiner) receivers and one macrodiversity SC receiver are analyzed. Independent κ-μ fading and correlated slow Gamma fading are present at the inputs to the microdiversity SC receivers. For this system model, analytical expression for the probability density of the signal at the output of the macrodiversity receiver SC, and the output capacity of the macrodiversity SC receiver are calculated. The obtained results are graphically presented to show the impact of Rician κ factor, the shading severity of the channel c, the number of clusters µ and correlation coefficient ρ on the probability density of the signal at the output of the macrodiversity system and channel capacity at the output of the macrodiversity system. Based on the obtained results it is possible to analyze the real behavior of the macrodiversity system in the presence of  κ-μ fading

Interventional Treatment of Abdominal Compartment Syndrome during Severe Acute Pancreatitis: Current Status and Historical Perspective

Abdominal compartment syndrome (ACS) in patients with severe acute pancreatitis (SAP) is a marker of severe disease. It occurs as combination of inflammation of retroperitoneum, visceral edema, ascites, acute peripancreatic fluid collections, paralytic ileus, and aggressive fluid resuscitation. The frequency of ACS in SAP may be rising due to more aggressive fluid resuscitation, a trend towards conservative treatment, and attempts to use a minimally invasive approach. There remains uncertainty about the most appropriate surgical technique for the treatment of ACS in SAP. Some unresolved questions remain including medical treatment, indications, timing, and interventional techniques. This review will focus on interventional treatment of this serious condition. First line therapy is conservative treatment aiming to decrease IAP and to restore organ dysfunction. If nonoperative measures are not effective, early abdominal decompression is mandatory. Midline laparostomy seems to be method of choice. Since it carries significant morbidity we need randomized studies to establish firm advantages over other described techniques. After ACS resolves efforts should be made to achieve early primary fascia closure. Additional data are necessary to resolve uncertainties regarding ideal timing and indication for operative treatment

Decompressive laparotomy with temporary abdominal closure versus percutaneous puncture with placement of abdominal catheter in patients with abdominal compartment syndrome during acute pancreatitis: background and design of multicenter, randomised, controlled study

<p>Abstract</p> <p>Background</p> <p>Development of abdominal compartment syndrome (ACS) in patients with severe acute pancreatitis (SAP) has a strong impact on the course of disease. Number of patients with this complication increases during the years due more aggressive fluid resuscitation, much bigger proportion of patients who is treated conservatively or by minimal invasive approach, and efforts to delay open surgery. There have not been standard recommendations for a surgical or some other interventional treatment of patients who develop ACS during the SAP. The aim of DECOMPRESS study was to compare decompresive laparotomy with temporary abdominal closure and percutaneus puncture with placement of abdominal catheter in these patients.</p> <p>Methods</p> <p>One hundred patients with ACS will be randomly allocated to two groups: I) decompresive laparotomy with temporary abdominal closure or II) percutaneus puncture with placement of abdominal catheter. Patients will be recruited from five hospitals in Belgrade during two years period. The primary endpoint is the mortality rate within hospitalization. Secondary endpoints are time interval between intervention and resolving of organ failure and multi organ dysfunction syndrome, incidence of infectious complications and duration of hospital and ICU stay. A total sample size of 100 patients was calculated to demonstrate that decompresive laparotomy with temporary abdominal closure can reduce mortality rate from 60% to 40% with 80% power at 5% alfa.</p> <p>Conclusion</p> <p>DECOMPRESS study is designed to reveal a reduction in mortality and major morbidity by using decompresive laparotomy with temporary abdominal closure in comparison with percutaneus puncture with placement of abdominal catheter in patients with ACS during SAP.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier: NTC00793715</p

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake