1,440 research outputs found

    The Effects of Mode Perceptions on Intercity Mode-Choice Behavior in Saudi Arabia

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    The conventional mode choice models mostly consider quantitative variables in their model estimation although mode choice may be affected by the qualitative perception levels of service variables. This study aimed to investigate the effect of incorporating mode perception into the modeling of mode choice process for intercity travel in Saudi Arabia after developing and testing scales for quantifying the perceptions of mode privacy, convenience, comfort and reliability. In order to investigate the effects of mode perceptions, multinomial logit mode choice models were calibrated for business trips as well as social/recreational trips. This study reveals that the perception of mode comfort significantly affects the choice of the travelers for the mentioned three types of trips but perception of mode is significant for business trips only. The study concluded that it is not worthy to use these variables in planning stages due to the difficulty and cost in obtaining the mode perceptions. However, the variables could be quite useful in identifying deficiencies of the intercity modes as perceived by travelers and therefore could help operators in improving the required services. Keywords: mode perception, mode choice

    RANCANG BANGUN GPS TRACKER PADA PERAHU NELAYAN BERBASIS INTERNET OF THINGS (IOT)

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    Nelayan adalah sebutan untuk orang yang bekerja setiap hari untuk menangkap ikan yang hidup di dasar kolom air, dan di permukaan. Perairan yang menjadi area kegiatan penangkapan ikan bisa berupa air tawar atau laut. Nelayan biasanya memiliki pangkalan perahu di mana mereka memarkir perahu mereka setelah menangkap ikan. Nelayan sering menjumpai situasi dimana perahu untuk penangkap ikan hilang di pangkalan karena dicuri atau terbawa arus laut. Meski sudah memiliki pengamanan yang cukup ketat, masalah tersebut masih kerap terjadi dan membuat resah para nelayan. Perkembangan teknologi saat ini diiringi dengan perkembangan teknologi smartphone. Setiap orang pasti memiliki smartphone. Perangkat keamanan perahu nelayan dapat dirancang melalui pemanfaatan smartphone. Smartphone yang terhubung dengan GPS melalui jaringan seluler dapat digunakan untuk memonitoring letak perahu nelayan melalui aplikasi Blynk dan memastikan kondisi perahu nelayan dalam keadaan baik. Selain meningkatkan nilai fungsi smartphone, alat ini juga meningkatkan rasa aman bagi pemilik perahu nelayan. GPS Tracker berhasil dibuktikan dalam penelitian ini dengan menghasilkan keakuratan dan monitoring perahu nelayan sebesar 90% aman

    Evaluation of Transportation Demand Management (TDM) Strategies and Its Prospect in Saudi Arabia

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    Nowadays it is reiterated in the literature to put more emphasis on Transportation Demand Management (TDM) strategies rather than the traditional transportation strategies which are based on “supply-side” tactic specifically in rapidly growing developing countries. The experiences of many cities reveal that as capacity is increased, demand increases at a similar rate, and subsequently in the long-term, drivers experience no net travel time advantages and the society suffers from the impacts of costly road bills and environmental degradation. This paper suggests emphasizing on TDM strategies to ensure sustainable transportation. The increasing trend of passenger cars in Saudi Arabia makes it more important to concentrate on TDM strategies as a tool for curbing vehicular pollution and congestion. This paper investigated the concept of TDM strategies focusing on the effect of TDM strategies on vehicular emissions and congestion. The analysis of limited scale interviews with experts revealed that tele-working, E-government, electronic shopping, congestion and parking pricing, increased fuel pricing, preferential treatment of HOV, Light Rail Transit (LRT) might be the potential TDM measures. The concerned authorities should think of an innovative mode of public transit services and continuously improve the services to encourage people to switch to public transit. Finally, this paper recommends adopting a public participatory approach in developing TDM strategies which will significantly contribute in reducing vehicular emissions and congestion and ultimately ensure sustainable transportation

    Cone Penetration Testing For Field Density Prediction

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    This paper summarizes an experimental program for developing a pilot procedure to check and predict field densities of compacted soils using static cone penetration tests. Three sandy soils were tested. The testing program included both laboratory and field tests. On the basis of laboratory tests, density prediction curves were developed while field results were used to find a correlation to predict densities on the basis of measured penetration resistances. The results are rather encouraging and promising. It is anticipated that the presented methodology would be very effective for compaction quality control in large areas of sandy soils because it is fast, simple and causes minimum disturbance to the compacted soil

    Investigation of Natural Effective Gamma Dose Rates case study: Ardabil Province in Iran

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    Gamma rays pose enough energy to form charged particles and adversely affect human health. Since, the external exposure of human beings to natural environmental gamma radiation normally exceeds that from all man-made sources combined, natural background gamma dose rates and corresponding annual effective doses were determined for selected cities of Ardabil province from 2009 to 2010. Outdoor gamma dose rates were measured using an Ion Chamber Survey Meter in 105 locations in selected districts. Average absorbed dose for Ardabil, Sar-Ein, Germy, Neer, Shourabil Recreational Lake, and Kosar were determined as 265, 219, 344, 233, 352, and 358 nSvh-1, respectively. Although dose rates recorded for Germi and Kosar are comparable with some areas with high natural radiation background, however, the dose rates in other districts are well below the levels reported for such locations. Average annual effective dose due to indoor and outdoor gamma radiation for Ardabil province was estimated to be 1.73 (1.35-2.39) mSv, which is on average 2 times higher than the world population weighted average

    The association between hypertension and other cardiovascular risk factors among non-diabetic Saudis adults-A cross sectional study

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    Population specific associations between cardiovascular disease with various risk factors including pre-hypertension and hypertension were reported. We aimed to investigate the association of higher than optimal blood pressure with measures of dysglycemia, dyslipidemia, and markers of inflammation in non-diabetic Saudi adults hoping to improve current Saudi guidelines to prevent cardiovascular disease. Volunteers were recruited randomly from public healthcare centers in Jeddah. Demographic information, blood pressure (BP), and anthropometric measurements were taken. Fasting blood samples were drawn, then again following 1-hour oral glucose tolerance test. Glycated hemoglobin, fasting plasma glucose (FPG), lipid profile, highly sensitive C- reactive protein, gamma glutamyl transferase, and 1-hour plasma glucose were measured. Complete data was found for 742 men and 592 women. Pre-hypertension was found in 47.2% of men, and 24.7% of women, while 15.1% of men, and 14.6% of women were hypertensive. Means of measured variables differed significantly between normotensive, pre-hypertensive, and hypertensive groups of men and women in gender specific manner. Association between measured variables and elevated BP, and hypertension were assessed using logistic regression models. After adjustment for age, body mass index and waist circumference, elevated blood pressure was associated with elevated triglycerides in men, while hypertension was significantly associated with elevated fasting plasma glucose, total cholesterol, triglycerides, low density lipoprotein- cholesterol, and low high density lipoprotein- cholesterol in men, and elevated triglycerides, and total cholesterol in women. Therefore, it is strongly recommended to measure lipid profile, specifically TG, for all diagnosed pre-hypertensive and hypertensive patients in addition to FPG for men.Peer reviewe

    Anoctamin1 and c-Kit immunohistochemical study of interstitial cells of Cajal in the muscularis externa of human gastrointestinal tract

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    Background: Interstitial cells of Cajal )ICC) are widely distributed in human gastrointestinal (GI) tract  specially in the layer of muscularis externa between neurons and smooth muscles. They play a very important role of coordination of GI tract motility. The aims of this research were to study the morphology and distribution of ICC in the muscularis externa of the GI tract, using immunohistochemistry staining methods, to determine the distribution of immune reactivity of Anoctamin1 (Ano1) compared with c-Kit, and to determine if Ano1 is a reliable marker for ICC in human GI tract. Materials and methods: Specimens from the wall of stomach, small intestine, and colon were taken from human cadavers and processed for histological and immunohistochemical study using c-Kit and Ano1 primary antibodies. Results: ICC appeared as bipolar cells, not forming network, in both the circular and longitudinal muscle layers, while in the myenteric area they appeared as multipolar interconnected cells. They were unevenly distributed in and between the muscle layers of the muscularis externa of human GI tract. They were more numerous in the stomach followed by the colon then the small intestine, and more numerous in the myenteric area followed by the circular muscle layer then the longitudinal muscle layer, in the three organs. Our results also showed that Ano1 is a more reliable marker for human ICC than c-kit. Conclusions: ICC differed in morphology and were unevenly distributed between muscle layers of muscularis externa and between different parts of human GI tract

    Multi-user visible light communications: State-of-the-art and future directions

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    Visible light communications (VLC) builds upon the dual use of existing lighting infrastructure for wireless data transmission. VLC has recently gained interest as cost-effective, secure, and energy-efficient wireless access technology particularly for indoor user-dense environments. While initial studies in this area are mainly limited to single-user point-to-point links, more recent efforts have focused on multi-user VLC systems in an effort to transform VLC into a scalable and fully networked wireless technology. In this paper, we provide a comprehensive overview of multi-user VLC systems discussing the recent advances on multi-user precoding, multiple access, resource allocation, and mobility management. We further provide possible directions for future research in this emerging topic.King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia ; TÜBİTAKPublisher versio
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