Probability of symbol error for MPSK, MDPSK and noncoherent MPSK with MRC and SC space diversity in Nakagami-m fading channel

This paper derives analytically some simple closed form expressions for the average symbol error rate (SER) of M-ary phase shift keying (MPSK), M-ary differential phase shift keying (MDPSK) and noncoherent M-ary frequency shift keying (MFSK) over a Nakagami-m (1960) fading channel with L-fold maximal ratio combining (MRC) and selection combining (SC) space diversity reception. Numerical results demonstrate the error performance improvement by employing MRC and SC diversity reception in the above communications systems and show that MRC improves the error performance more significantly than does simple SC.published_or_final_versio

Systematic review and meta-analysis of studies of biliary reconstruction in adult living donor liver transplantation

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Performance of generalized selection combining for mobile radio communications with mixed cochannel interferers

The performance of generalized selection combining (GSC) space diversity for mobile radio systems in the presence of multiple cochannel interferers is studied. Two cochannel interference models are considered: 1) L cochannel interferers consisting of L-N Nakagami-m interferers and N Rayleigh interferers and 2) L cochannel interferers in which each interferer follows Nakagami-m distribution for a fraction of time and Rayleigh distribution for the remaining of time. The fading parameters of the Nakagami-m interferers are limited to integer values only. The desired signal is assumed to be Rayleigh faded. Also, all the desired signals and the cochannel interferers received on each branch are independent of each other. Closed-form expressions are derived for the probability density functions (pdfs) of the instantaneous signal-to-interference power ratio (SIR) at the output of the GSC for the two cochannel interference models. Using these SIR pdfs, closed-form expression for evaluating the outage probability and the average bit error probability (BEP) are subsequently derived. A differential phase-shift keying scheme is considered in the derivation. Numerical results showing the influences of various system parameters on the outage probability and the average BEP are then presented.published_or_final_versio

Approximate BER performance of generalized selection combining in Nakagami-m fading

The error performance of generalized selection combining (GSC), which optimally combines the K highest signal-to-noise ratio (SNR) signals out of L total diversity signals, in Nakagami-m fading was recently evaluated using moment generating function (MGF) of the GSC output SNR. However, no single closed-form expression for the MGF exists for arbitrary K and L. In fact, closed-form expression for the MGF is possible only for individual combination of K and L. In this letter, a single closed-form expression for approximating the MGF is, therefore, derived and employed in evaluating the approximate error performance. Although the approximation is only applicable for GSC with K being a factor of L, it nonetheless achieves a high degree of accuracy.published_or_final_versio

Performance analysis of bandwidth efficient coherent modulation schemes with L-fold MRC and SC in Nakagami-m fading channels

This paper presents the average symbol error rates (SERs) of the 16-ary phase shift keying (16PSK), 16-ary amplitude phase shift keying (16APSK) and 16-ary quadrature amplitude modulation (16QAM) with L-fold maximal ratio combining (MRC) and selection combining (SC) space diversity receptions over Nakagami-m fading channels. Numerical results manifested error performance improvement when L-fold MRC and SC diversity receptions were employed. Error performance improvement attributed to an L=2 MRC diversity reception is comparable with that attributed to an L=4 SC diversity reception for the above three 16-ary modulation systems in a Nakagami-m fading channel with m of 5.published_or_final_versio

Laparoscopic liver resection for hepatocellular carcinoma in patients with cirrhosis

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Acute puerperal uterine inversion : Case report

Acute puerperal uterine inversion is a rare potentially life-threatening complication of the third stage of labour that should be expeditiously managed to avert maternal mortality. A 21-year primigravida who was admitted in labour had a spontaneous vertex delivery and her third stage of labour was complicated by uterine inversion. Manual repositioning of the uterus failed, but was successfully accomplished by Haltains surgical procedure. Prompt recognition and treatment is vital for successful management of acute uterine inversion

The changing epidemiology of recurrent pyogenic cholangitis

Recurrent pyogenic cholangitis is prevalent in Hong Kong and East Asia. While the recent influx of Asian immigrants has resulted in more cases appearing in the West, over the past three decades, the overall incidence in East Asia has been in decline. The experience of the Queen Mary Hospital and other hospitals in the region has been confirmed by comprehensive surveys. The decline in incidence has been attributed to the improved economic situation and living standards with the associated westernisation of diet.published_or_final_versio

Infectious complications of liver transplantation

Sixteen (50%) of the 32 patients who received liver transplantations from October 1991 to March 1993 at Queen Mary Hospital, Hong Kong, developed viral, bacterial, or fungal infections. The viral infections were largely a result of immunosuppression while accidental bowel perforation, bile leak at the anastomosis, and delayed onset of stricture of the bile duct anastomosis were responsible for the intra-abdominal bacterial or fungal infections. Although the incidence of infectious complications was high, all patients were managed effectively and only one patient with lymphoproliferative disorder died. Infectious complications can lead to a prolonged hospital stay and a substantially increased hospital cost. The adoption of new immunosuppressive regimes that can better prevent acute graft rejection and adherence to meticulous surgical technique will help to reduce the infectious complications of liver transplantation in the future.published_or_final_versio

Combined diversity sequence estimation receiver for wideband digital mobile radio

An investigation is presented into the performance of a novel type of sequence estimation equalisation receiver. The receiver incorporates space diversity to further enhance the signal reception in multipath fading environments. It is shown that the receiver complexity is reduced by approx. 90% with virtually no performance loss compared to that of the MLSE.published_or_final_versio