Rate adaptation for 802.11 multiuser mimo networks

In multiuser MIMO (MU-MIMO) networks, the optimal bit rate of a user is highly dynamic and changes from one packet to the next. This breaks traditional bit rate adaptation algorithms, which rely on recent history to predict the best bit rate for the next packet. To address this problem, we introduce TurboRate, a rate adaptation scheme for MU-MIMO LANs. TurboRate shows that clients in a MU-MIMO LAN can adapt their bit rate on a per-packet basis if each client learns two variables: its SNR when it transmits alone to the access point, and the direction along which its signal is received at the AP. TurboRate also shows that each client can compute these two variables passively without exchanging control frames with the access point. A TurboRate client then annotates its packets with these variables to enable other clients to pick the optimal bit rate and transmit concurrently to the AP. A prototype implementation in USRP-N200 shows that traditional rate adaptation does not deliver the gains of MU-MIMO WLANs, and can interact negatively with MU-MIMO, leading to low throughput. In contrast, enabling MU-MIMO with TurboRate provides a mean throughput gain of 1.7x and 2.3x, for 2-antenna and 3-antenna APs respectively.National Science Council (China) (contract No. NSC 100-2221-E-001-005-MY2)National Science Foundation (U.S.) (NSF Grant CNS-1117194

Sustainabilitas Arsitektur Masjid: Evaluasi Konsep “Simple Architecture” sebagai Implementasi Desain Arsitektur Berkelanjutan suatu Kawasan

Makalah ini membahas aspek-aspek “kesederhanaan” (simplicity) sebagai konsep desain bangunan masjid secara berkelanjutan (sustainable) sesuai konteks dengan mengambil studi kasus masjid kawasan Al-Irsyad Satya Kota Baru Parahyangan, Bandung. Masjid sebagai subyek arsitektur dan pusat ibadah menjadi ruang publik yang didesain dari elemen-elemen yang secara ideal mengandung nilai-nilai Islam dan bertujuan mendukung fungsinya. Desain masjid berkonsep simple atau “sederhana” digunakan sebagai alternatif kontemporer untuk mengoptimalisasi fungsi tersebut, meliputi struktur bangunan hingga biaya pemeliharaan (maintenance) sesuai prinsip keberlanjutan. Keterkaitan erat bangunan masjid dengan aktivitas masyarakat berpotensi melibatkan partisipasi masyarakat dan pengelola dalam menerapkan program sustainabilitas sesuai konteks lingkungannya. Metode yang digunakan dalam penelitian ini berbasis pendekatan Grounded Theory secara kualitatif melalui pengumpulan data dari kegiatan observasi, interview dan analisis program keberlanjutan kawasan. Penelitian menemukan keterkaitan konsep “sederhana” yang mendukung sustainabilitas desain sekaligus menggarisbawahi evaluasi konsep desain “sederhana” yang hadir serta faktor pemeliharaan/pengembangan masjid dan kawasan

Pronunciation Modeling for Spontaneous Speech Recognition using Latent Pronunciation Analysis (LPA) and Prior Knowledge

In this paper, we propose a new framework for pronunciation modeling, in which the search algorithm tries to focus primarily on the clearly-pronounced portion of speech, while deemphasizing the observations of the slurred portion. This is based on the prior analysis that the pronunciation variation has to do with the predictability and the importance of the words in the spoken utterances, which may be estimated to some extent. We define a set of pronunciation-related features and develop a Latent Pronunciation Analysis (LPA) to estimate the "latent pronunciation states " in the speech. The LPA probabilities, pronunciation-related features and another set of prior knowledge obtained from two distance measures between phonemes are integrated in a SVM classifier to produce a "pronunciation variation indicator " for each frame, based on which the Viterbi decoding was performed. Very encouraging initial results on Mandarin spontaneous speech were obtained in preliminary experiments. Index Terms- Pronunciation variation, spontaneous speech, speech recognition, Probabilistic Latent Semantic Analysis, Distance metrics

Spontaneous Mandarin Speech Recognition with Disfluencies Detected by Latent Prosodic Modeling (LPM)

In this paper, a new approach for improved spontaneous Mandarin speech recognition using Latent Prosodic Modeling (LPM) for disfluency interruption point (IP) detection is presented. The basic idea is to detect the disfluency interruption points (IPs) prior to the recognition, and then to incorporate these information into the recognition process via the second pass rescoring. For accurate detection of disfluency interruption points (IPs), prosodic information from local to global, from observable to latent, were integrated using the proposed Latent Prosodic Modeling (LPM). A whole set of new features were first defined for each syllable boundary obtained in the first pass recognition by carefully considering the special characteristics of Mandarin Chinese, and the importance of each feature with respect to each disfluency type was analyzed. Then, a set of prosodic characters, prosodic terms, and prosodic documents were defined to be used in the Probabilistic Latent Semantic Analysis (PLSA), based on which the prosody can be modeled using a set of prosodic states representing various latent factors such as speakers, speaking rate, utterance modality, intonatio

A Neutral Risk on the Development of New-Onset Diabetes Mellitus (NODM) in Taiwanese Patients with Dyslipidaemia Treated with Fibrates

There are no data on the incidence of new-onset diabetes mellitus (NODM ) in nondiabetic dyslipidaemia patients treated with fibrates. The aim of our study was to clarify these issues, to investigate the relationship between NODM and fibrate and whether the fibrates lead to increased risk for developing NODM. A retrospective cohort study was conducted by analyzing the Longitudinal Health Insurance Database (LHID 2005) of the National Health Insurance Research Database (NHIRD) from 2005 to 2010 to investigate all fibrate prescriptions for patients with dyslipidaemia. We estimated the hazard ratios (HRs) of NODM associated with fibrate use. We identified 145 NODM patients among 3,815 dyslipidaemic patients in the database for the study period. The risk estimates for NODM for users of fenofibrate (HR 1.30; 95% CI 0.82, 2.05) and gemfibrozil (HR 0.771; 95% CI 0.49, 1.22) were not associated with an increased risk of developing NODM (P>0.05). Our results revealed that patients with dyslipidaemia who took fenofibrate and gemfibrozil had a neutral risk of NODM. The reasons may be associated with the fibrates have the properties that activate PPARα and in some cases also activated PPARγ, leading to showing a neutral risk of NODM