225 research outputs found
“Throughput Performance of ARQ Schemes Based on Punctured Turbo codes in Rayleigh Fading Channels”
The astonishing performance of turbo codes can be used to enhance the throughput efficiency of data networks based on automatic report request. In wireless channels, the throughput can be maximized by adaptively matching the error correction capability of the code to the prevailing channel conditions. This paper investigates the throughput efficiency of hybrid ARQ based on punctured turbo codes. The throughput is enhanced when code sets are designed along the guidelines of good puncturing patterns
“Bit Error Rate Performance Analysis of a Threshold-Based Generalized Selection Combining Scheme in Nakagami Fading Channels”
The severity of fading on mobile communication channels calls for the combining of multiple diversity sources to achieve acceptable error rate performance. Traditional approaches perform the combining of the different diversity sources using either the conventional selective diversity combining (CSC), equal-gain combining (EGC), or maximal-ratio combining (MRC) schemes. CSC and MRC are the two extremes of compromise between performance quality and complexity. Some researches have proposed a generalized selection combining scheme (GSC) that combines the best M branches out of the L available diversity resources (M ≤ L). In this paper, we analyze a generalized selection combining scheme based on a threshold criterion rather than a fixed-size subset of the best channels. In this scheme, only those diversity branches whose energy levels are above a specified threshold are combined. Closed-form analytical solutions for the BER performances of this scheme over Nakagami fading channels are derived. We also discuss the merits of this scheme over GSC
“Bit Error Rate Performance Analysis of a Threshold-Based Generalized Selection Combining Scheme in Nakagami Fading Channels”
The severity of fading on mobile communication channels calls for the combining of multiple diversity sources to achieve acceptable error rate performance. Traditional approaches perform the combining of the different diversity sources using either the conventional selective diversity combining (CSC), equal-gain combining (EGC), or maximal-ratio combining (MRC) schemes. CSC and MRC are the two extremes of compromise between performance quality and complexity. Some researches have proposed a generalized selection combining scheme (GSC) that combines the best M branches out of the L available diversity resources (M ≤ L). In this paper, we analyze a generalized selection combining scheme based on a threshold criterion rather than a fixed-size subset of the best channels. In this scheme, only those diversity branches whose energy levels are above a specified threshold are combined. Closed-form analytical solutions for the BER performances of this scheme over Nakagami fading channels are derived. We also discuss the merits of this scheme over GSC
“Bit Error Rate Performance Analysis of a Threshold-Based Generalized Selection Combining Scheme in Nakagami Fading Channels”
The severity of fading on mobile communication channels calls for the combining of multiple diversity sources to achieve acceptable error rate performance. Traditional approaches perform the combining of the different diversity sources using either the conventional selective diversity combining (CSC), equal-gain combining (EGC), or maximal-ratio combining (MRC) schemes. CSC and MRC are the two extremes of compromise between performance quality and complexity. Some researches have proposed a generalized selection combining scheme (GSC) that combines the best M branches out of the L available diversity resources (M ≤ L). In this paper, we analyze a generalized selection combining scheme based on a threshold criterion rather than a fixed-size subset of the best channels. In this scheme, only those diversity branches whose energy levels are above a specified threshold are combined. Closed-form analytical solutions for the BER performances of this scheme over Nakagami fading channels are derived. We also discuss the merits of this scheme over GSC
“Throughput Performance of ARQ Schemes Based on Punctured Turbo codes in Rayleigh Fading Channels”
The astonishing performance of turbo codes can be used to enhance the throughput efficiency of data networks based on automatic report request. In wireless channels, the throughput can be maximized by adaptively matching the error correction capability of the code to the prevailing channel conditions. This paper investigates the throughput efficiency of hybrid ARQ based on punctured turbo codes. The throughput is enhanced when code sets are designed along the guidelines of good puncturing patterns
GeneProf data:a resource of curated, integrated and reusable high-throughput genomics experiments
GeneProf Data (http://www.geneprof.org) is an open web resource for analysed functional genomics experiments. We have built up a large collection of completely processed RNA-seq and ChIP-seq studies by carefully and transparently reanalysing and annotating high-profile public data sets. GeneProf makes these data instantly accessible in an easily interpretable, searchable and reusable manner and thus opens up the path to the advantages and insights gained from genome-scale experiments to a broader scientific audience. Moreover, GeneProf supports programmatic access to these data via web services to further facilitate the reuse of experimental data across tools and laboratories
Mobile measurements of ship emissions in two harbour areas in Finland
Four measurement campaigns were performed in two
different environments – inside the harbour areas in the city centre of
Helsinki, and along the narrow shipping channel near the city of Turku,
Finland – using a mobile laboratory van during winter and summer conditions in 2010–2011. The
characteristics of gaseous (CO, CO2, SO2, NO, NO2,
NOx) and particulate (number and volume size distributions as
well as PM2.5) emissions for 11 ships regularly operating on the Baltic
Sea were studied to determine the emission parameters. The highest particle
concentrations were 1.5 × 106 and 1.6 × 105 cm−3 in
Helsinki and Turku, respectively, and the particle number size distributions
had two modes. The dominating mode peaked at 20–30 nm, and the
accumulation mode at 80–100 nm. The majority of the particle mass was
volatile, since after heating the sample to 265 °C, the particle
volume of the studied ship decreased by around 70%. The emission factors
for NOx varied in the range of 25–100 g (kg fuel)−1, for
SO2 in the range of 2.5–17.0 g (kg fuel)−1, for particle number in the range of
(0.32–2.26) × 1016 # (kg fuel)−1, and for
PM2.5 between 1.0–4.9 g (kg fuel)−1. The ships equipped with
SCR (selective catalytic reduction) had the lowest NOx emissions,
whereas the ships with DWI (direct water injection) and HAMs (humid air motors)
had the lowest SO2 emissions but the highest particulate emissions. For all
ships, the averaged fuel sulphur contents (FSCs) were less than 1% (by
mass) but none of them was below 0.1% which will be the new EU
directive starting 1 January 2015 in the SOx emission control
areas; this
indicates that ships operating on the Baltic Sea will face large challenges
Resorbable screws versus pins for optimal transplant fixation (SPOT) in anterior cruciate ligament replacement with autologous hamstring grafts: rationale and design of a randomized, controlled, patient and investigator blinded trial [ISRCTN17384369]
BACKGROUND: Ruptures of the anterior cruciate ligament (ACL) are common injuries to the knee joint. Arthroscopic ACL replacement by autologous tendon grafts has established itself as a standard of care. Data from both experimental and observational studies suggest that surgical reconstruction does not fully restore knee stability. Persisting anterior laxity may lead to recurrent episodes of giving-way and cartilage damage. This might at least in part depend on the method of graft fixation in the bony tunnels. Whereas resorbable screws are easy to handle, pins may better preserve graft tension. The objective of this study is to determine whether pinning of ACL grafts reduces residual anterior laxity six months after surgery as compared to screw fixation. DESIGN/ METHODS: SPOT is a randomised, controlled, patient and investigator blinded trial conducted at a single academic institution. Eligible patients are scheduled to arthroscopic ACL repair with triple-stranded hamstring grafts, conducted by a single, experienced surgeon. Intraoperatively, subjects willing to engage in this study will be randomised to transplant tethering with either resorbable screws or resorbable pins. No other changes apply to locally established treatment protocols. Patients and clinical investigators will remain blinded to the assigned fixation method until the six-month follow-up examination. The primary outcome is the side-to-side (repaired to healthy knee) difference in anterior translation as measured by the KT-1000 arthrometer at a defined load (89 N) six months after surgery. A sample size of 54 patients will yield a power of 80% to detect a difference of 1.0 mm ± standard deviation 1.2 mm at a two-sided alpha of 5% with a t-test for independent samples. Secondary outcomes (generic and disease-specific measures of quality of life, magnetic resonance imaging morphology of transplants and devices) will be handled in an exploratory fashion. CONCLUSION: SPOT aims at showing a reduction in anterior knee laxity after fixing ACL grafts by pins compared to screws
Input-Adaptive Proxy for Black Carbon as a Virtual Sensor
Missing data has been a challenge in air quality measurement. In this study, we develop an input-adaptive proxy, which selects input variables of other air quality variables based on their correlation coefficients with the output variable. The proxy uses ordinary least squares regression model with robust optimization and limits the input variables to a maximum of three to avoid overfitting. The adaptive proxy learns from the data set and generates the best model evaluated by adjusted coefficient of determination (adjR2). In case of missing data in the input variables, the proposed adaptive proxy then uses the second-best model until all the missing data gaps are filled up. We estimated black carbon (BC) concentration by using the input-adaptive proxy in two sites in Helsinki, which respectively represent street canyon and urban background scenario, as a case study. Accumulation mode, traffic counts, nitrogen dioxide and lung deposited surface area are found as input variables in models with the top rank. In contrast to traditional proxy, which gives 20–80% of data, the input-adaptive proxy manages to give full continuous BC estimation. The newly developed adaptive proxy also gives generally accurate BC (street canyon: adjR2 = 0.86–0.94; urban background: adjR2 = 0.74–0.91) depending on different seasons and day of the week. Due to its flexibility and reliability, the adaptive proxy can be further extend to estimate other air quality parameters. It can also act as an air quality virtual sensor in support with on-site measurements in the future
Input-Adaptive Proxy for Black Carbon as a Virtual Sensor
Missing data has been a challenge in air quality measurement. In this study, we develop an input-adaptive proxy, which selects input variables of other air quality variables based on their correlation coefficients with the output variable. The proxy uses ordinary least squares regression model with robust optimization and limits the input variables to a maximum of three to avoid overfitting. The adaptive proxy learns from the data set and generates the best model evaluated by adjusted coefficient of determination (adjR2). In case of missing data in the input variables, the proposed adaptive proxy then uses the second-best model until all the missing data gaps are filled up. We estimated black carbon (BC) concentration by using the input-adaptive proxy in two sites in Helsinki, which respectively represent street canyon and urban background scenario, as a case study. Accumulation mode, traffic counts, nitrogen dioxide and lung deposited surface area are found as input variables in models with the top rank. In contrast to traditional proxy, which gives 20–80% of data, the input-adaptive proxy manages to give full continuous BC estimation. The newly developed adaptive proxy also gives generally accurate BC (street canyon: adjR2 = 0.86–0.94; urban background: adjR2 = 0.74–0.91) depending on different seasons and day of the week. Due to its flexibility and reliability, the adaptive proxy can be further extend to estimate other air quality parameters. It can also act as an air quality virtual sensor in support with on-site measurements in the future
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