Rapid design of tool-wear condition monitoring systems for turning processes using novelty detection

Condition monitoring systems of manufacturing processes have been recognised in recent years as one of the key technologies that provide the competitive advantage in many manufacturing environments. It is capable of providing an essential means to reduce cost, increase productivity, improve quality and prevent damage to the machine or workpiece. Turning operations are considered one of the most common manufacturing processes in industry. It is used to manufacture different round objects such as shafts, spindles and pins. Despite recent development and intensive engineering research, the development of tool wear monitoring systems in turning is still ongoing challenge. In this paper, force signals are used for monitoring tool-wear in a feature fusion model. A novel approach for the design of condition monitoring systems for turning operations using novelty detection algorithm is presented. The results found prove that the developed system can be used for rapid design of condition monitoring systems for turning operations to predict tool-wear

The design of an effective sensor fusion model for condition monitoring systems of turning processes

High energy price and the increasing requirements of quality and low cost of products have created an urgent need to implement new technologies in current automated manufacturing environments. Condition monitoring systems of manufacturing processes have been recognised in recent years as one of the essential technologies that provide the competitive advantage in many manufacturing environments. This research aims to develop an effective sensor fusion model for turning processes for the detection of tool wear. Multi-sensors combined with a novelty detection algorithm and Learning Vector Quantisation (LVQ) neural networks are used in this research to detect tool wear and provide diagnostic and prognostic information. A novel approach, termed ASPST, (Automated Sensor and Signal Processing Selection System for Turning) is used to select the most appropriate sensors and signal processing methods. The aim is to reduce the number of sensors needed in the overall system and reduce the cost. The ASPST approach is based on simplifying complex sensory signals into a group of Sensory Characteristic Features (SCFs) and evaluating the sensitivity of these SCFs in detecting tool wear. A wide range of sensory signals (cutting forces, strain, acceleration, acoustic emission and sound) and signal processing methods are also implemented to verify the capability of the approach. A cost reduction method is also implemented based on eliminating the least utilised sensor in an attempt to reduce the overall cost of the system without sacrificing the capability of the condition monitoring system. The experimental results prove that the suggested approach provides a responsive and effective solution in monitoring tool wear in turning with reduced time and cost

On The Queuing System M/Er/1/N

In this paper the queuing system (M/Er/1/N) has been considered in equilibrium. The method of stages introduced by Erlang has been used. The system of equations which governs the equilibrium probabilities of various stages has been given. For general N the probability of j stages of service are left in the system, has been introduced. And the probability for the empty system has been calculated in the explicit form

The Perception of English Vowels by Arab EFL Learners: A Case Study of University Students at Zarqa University

The present paper focuses on the perception of English vowel sounds by learners of English at university level. English and Arabic, genetically two different languages, share some common features on one hand, and exhibit a lot of differences on the other hand. These differences are the chief source of difficulty in the learning of a foreign language. Some Arabic speakers perform oddly on a range of experimental tasks which involve word discrimination. All these tasks involve discriminating words with identical consonant patterns, but differing in their vowels. Some Arabic speakers, it seems, are conspicuously inaccurate in handling vowels in English words, and are much more prone to make errors involving vowels than subjects of other mother tongue backgrounds. One possible explanation to these effects is that Arabic speakers seem to transfer to English a set of psycholinguistic strategies that are more appropriately deployed in processing Arabic words. Unlike English, Arabic vowels are of secondary importance both in script and in word building, and the word recognition system depends heavily on the tri-consonantal roots which are the basis of most Arabic words with vowels variations placed within the consonantal framework. From pedagogy point of view, such differences between the two languages will be determined and included in various teaching material. In some other words, teaching will be directed at those differences. This in turn determines what the teacher has to teach and what the learner has to learn. The present researchers anticipate that the similarities between the two systems would act as a reference point for the learner's perception of the English vowels. The results of the present research would in turn encourage instructors to follow similar procedures in their teaching of sounds at university level in particular. Keywords: English as a foreign language (EFL), Modern Standard Arabic, Zarqa Universit

Prevalence of oral mucosal lesions in psoriatic patients: a controlled study

Objectives: This study aimed to investigate and compare the prevalence of oral mucosal lesions in a group of psoriatic patients and healthy subjects, and its correlation to multiple clinical parameters. Study design: 100 psoriatic patients and 100 closely matched controls underwent clinical oral examination. Oral lesions were diagnosed according to the criteria proposed by the World Health Organization (WHO). The patients filled the Hospital Anxiety and Depression (HAD) questionnaire and the Dermatology Life Quality Index (DLQI). The severity of psoriasis was assessed by the Psoriasis Area and Severity Index (PASI). Categorical variables were evaluated using Chi-square test or Fisher's exact test with overall significance set at p< 0.05. Results: Oral mucosal lesions were diagnosed in 43 (43%) psoriatic patients and 17 (17%) control subjects (p=0.000). Comparing psoriatic patients to control subjects the prevalence of fissured tongue (FT) was 35% vs. 13% (p=0.000); geographic tongue (GT) 17% vs. 9% (p=0.09); combination of FT and GT 5% vs. 5% (p=1.00); oral candidosis 3% vs. 0% (p=0.81); leukoedema 1% vs. 3% (p=0.62); physiologic melanin pigmentations 4% vs. 1% (p=0.37) respectively. The clinical type of psoriasis, duration of the disease, method of disease management (medicated vs. non-medicated for psoriasis), smoking habit, psychological status or the disease severity did not influence the prevalence of FT and GT. Psoriatic patients who experienced 'very large' to 'extremely large' adverse effect of psoriasis on their quality of life have significantly higher prevalence of GT (p=0.04). Conclusions: FT is significantly more common in psoriatic patients compared to controls; hence studies investigating the nature of this relationship are warranted. Oral health care providers should be aware of the predisposition of psoriatic patients to oral candidosis

Millimeter wave propagation measurements and characteristics for 5G system

In future 5G systems, the millimeter wave (mmWave) band will be used to support a large capacity for current mobile broadband. Therefore, the radio access technology (RAT) should be made available for 5G devices to help in distinct situations, for example device-to-device communications (D2D) and multi-hops. This paper presents ultra-wideband channel measurements for millimeter wave bands at 19, 28, and 38 GHz. We used an ultra-wideband channel sounder (1 GHz bandwidth) in an indoor to outdoor (I2O) environment for non-line-of-sight (NLOS) scenarios. In an NLOS environment, there is no direct path (line of sight), and all of the contributed paths are received from different physical objects by refection propagation phenomena. Hence, in this work, a directional horn antenna (high gain) was used at the transmitter, while an omnidirectional antenna was used at the receiver to collect the radio signals from all directions. The path loss and temporal dispersion were examined based on the acquired measurement data—the 5G propagation characteristics. Two different path loss models were used, namely close-in (CI) free space reference distance and alpha-beta-gamma (ABG) models. The time dispersion parameters were provided based on a mean excess delay, a root mean square (RMS) delay spread, and a maximum excess delay. The path loss exponent for this NLOS specific environment was found to be low for all of the proposed frequencies, and the RMS delay spread values were less than 30 ns for all of the measured frequencies, and the average RMS delay spread values were 19.2, 19.3, and 20.3 ns for 19, 28, and 38 GHz frequencies, respectively. Moreover, the mean excess delay values were found also at 26.1, 25.8, and 27.3 ns for 19, 28, and 38 GHz frequencies, respectively. The propagation signal through the NLOS channel at 19, 28, and 38 GHz was strong with a low delay; it is concluded that these bands are reliable for 5G systems in short-range applications

Prevalence and Diffusion of Gastrointestinal Parasite Infections in Swamp Water Buffalo (Bubalus Bubalis) Populations from Marshlands of Iraq

Background and objectives: New information on the epidemiology of gastrointestinal (GI) parasite infection in water buffaloes is crucial for understanding their risk factors and transmission. The objectives of this study were (1) to determine the prevalence of GI parasites in buffaloes in the Marshland areas of southern Iraq, and (2) to evaluate the association of risk factors with the parasitic infections.Materials and Methods: A total of 166 water buffaloes from the Marshland in the north of Basra (n=75), and Thi-Qar (n=91) provinces from November 2016 to April 2017 were enrolled. Fecal samples were collected and examined for the presence of helminth eggs and protozoal oocysts using sedimentation-flotation and centrifugal flotation techniques.Results: The overall prevalence of infection in buffaloes was 82% (136/166), with the highest number of single parasite infection (64%), followed by those with double (29%) and triple (7%) parasite infections. The most frequently identified parasites were Fasciola spp. (23%, 39/166), Eimeria spp. (19%, 32/166), Toxocara vitulorum (13%, 21/166), Trichostrongylus spp. (12%, 20/166), and Oesophagostomum spp. (10%, 10/166). Moniezia spp. was the only identified cestode with a prevalence of (8%, 13/166). A significant association was reported between feeding type and parasitic infections with Eimeria spp., Trichostrongylus spp., Moniezia spp., Trichuris spp., and Ostertagia ostertagia.Conclusion: The prevalence of GI parasitic infection in buffaloes raised in the Marshlands is high, indicating a high intensity of natural infection. The findings of this study imply an urgent need for the implementation of efficient control measures against parasitic infections in the Marshlands

Perceived causes of prescribing errors by physicians: A qualitative study

Purpose: To explore physicians’ perceived causes of prescribing errors in Saudi hospitals.Methods: This qualitative study was conducted in three tertiary hospitals in Riyadh, Saudi Arabia: two academic and one government military hospital. A total of 13 physicians from three hospitals participated in two focus groups. Discussions were audiotaped and transcribed verbatim. Transcripts were analysed using thematic content analysis and categorised into themes of error-producing conditions, latent conditions and both successful and unsuccessful defences, based on Reason’s Accident Causation Model.Results: Error-producing conditions included the prescriber, the work environment, the team, the task, the patient and the computer system. The most commonly cited category related to the prescriber’s skills and knowledge. The most important latent conditions reported were a shortage of clinical pharmacists followed by lack of computerised physician order entry. The major unsuccessful defences were appropriate references and internet facilities, which were often unavailable.Conclusion: Several causes of prescribing errors were identified. Lack of clinical pharmacists and lack of computerised prescribing systems are the key issues.Keywords: Prescribing errors, Qualitative study, Computerized prescribing system, Reason’s accident causation mode

Window-based channel impulse response prediction for time-varying ultra-wideband channels

This work proposes channel impulse response (CIR) prediction for time-varying ultra-wideband (UWB) channels by exploiting the fast movement of channel taps within delay bins. Considering the sparsity of UWB channels, we introduce a window-based CIR (WB-CIR) to approximate the high temporal resolutions of UWB channels. A recursive least square (RLS) algorithm is adopted to predict the time evolution of the WB-CIR. For predicting the future WB-CIR tap of window wk, three RLS filter coefficients are computed from the observed WB-CIRs of the left wk-1, the current wk and the right wk+1 windows. The filter coefficient with the lowest RLS error is used to predict the future WB-CIR tap. To evaluate our proposed prediction method, UWB CIRs are collected through measurement campaigns in outdoor environments considering line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. Under similar computational complexity, our proposed method provides an improvement in prediction errors of approximately 80% for LOS and 63% for NLOS scenarios compared with a conventional method