RESEARCH BACKGROUND. Commercial trucks are an important component of our regional economic activity. As a consequence, freeway usage and performance patterns that affect trucking activities have potentially serious impacts on commercial, industrial, and transport-related business throughout the Puget Sound region. Furthermore, since heavy weights and large turning radii make the characteristics of truck movements quite different from those of passenger cars, the monitoring of freight movements is imperative for successful traffic management, planning, and policy analysis programs. In September 1999, the Washington State Department of Transportation (WSDOT) initiated a research project entitled “Monitoring Freight on Puget Sound Freeways.” Its objectives were to enhance the FLOW system evaluation methodology and supplement the tool set that is now used to analyze vehicle usage and performance on the central Puget Sound freeway network. The methodology and tool set enhancements would enable analysts to produce estimates of the size and performance of freight (truck) movements on Puget Sound freeways and help monitor trends in trucking activities over time. By using vehicle length categories as a surrogate for various categories of trucks, the nature of trucking activities in the region could be estimated. To produce volume data sorted by vehicle length categories, the dual-loop data collected by the WSDOT FLOW system were selected as the main data source for the project. Unfortunately, preliminary tests performed on the dual-loop data indicated that these data were not reliable. Consequently, a part of the project was temporarily suspended until the accuracy of the dual-loop data could be improved or a better data source found. Because dual-loop detectors, if sufficiently accurate, can be extremely cost- effective collectors of real-time vehicle classification and speed data, further research on the existing problem and potential remedies was sought. The current project addressed this concern by performing further analyses of dual-loop data inaccuracies, investigating the types and potential causes of these inaccuracies, and proposing necessary steps to improve data quality.
RESEARCH BACKGROUND. Transit signal priority (TSP) is an operational strategy that facilitates the movement of in- service transit vehicles through signalized intersections. Because transit vehicle delays at signalized intersections typically account for 10 to 20 percent of transit vehicle running times, TSP promotes transit utilization by improving service reliability (Bakers 2002). Through customer service enhancements, the transit agency could ultimately attract more customers. As an important intelligent transportation systems (ITS) technology, TSP systems use sensors to detect approaching transit vehicles and alter signal timings, if necessary, to prioritize transit vehicle passage and improve their performance. For example, a green signal can be extended for a late transit vehicle to avoid further delay at the intersection. By reducing the waiting time of transit vehicles at intersections, TSP can reduce transit delay and travel time, thereby increasing reliability and quality of service. Implementation of TSP gives transit customers more dependable service through greater schedule adherence and a more comfortable ride as a result of a decreased number of stops and braking at signalized intersections. Transit riders who have experienced smoother and more comfortable rides are more likely to continue using transit services. Besides improving service, a second objective for using TSPs is to decrease costs (Xxxxxx and Xxxxxxxxx 1997). Fewer stops can mean reductions in drivers’ workload, travel time, fuel consumption, vehicle emissions, and maintenance costs. Reductions in bus running times and number of stops may also lower vehicle wear and tear, and consequently lead to deferred vehicle maintenance and new vehicle purchases (Xxxxxx and Xxxxxxxxx 1997). Greater fuel economy and reduced maintenance costs can increase the efficiency of transit operations. TSP can also help reduce transit operation costs, as reductions in transit vehicle travel times may allow a given level of service to be offered with fewer transit vehicles. Local transportation agencies also can benefit from TSP strategies when improved transit service encourages more auto users to switch to public transportation. Finally, reduced demand for personal car travel will help improve roadway service level. Because of the rapid population and economic growth in the greater Seattle area, traffic congestion has become an increasingly important issue. Improving transit services to reduce personal car travel demand ...
RESEARCH BACKGROUND. Traffic speed is one of the most important variables for traffic operations and control. It is both a potential sign of problems on the roadway and a good measure of system effectiveness. Many incident detection algorithms are based on traffic speed data. Speed variation is also a good indicator of traffic safety (Xxxxxxxx and Xxxxxxx, 2000). If good network-wide speed information is available, the travel time for any origin- destination pair can be calculated. Data concerning trucks and heavy vehicles are important for several reasons. Because of their heavy weight and large turning radii, long vehicles (LVs) have very different moving characteristics than short vehicles (SVs), which are mostly passenger cars. This affects a roadway’s geometric design factors, such as horizontal alignment and curb heights. The heavy weight of such vehicles is also an important factor in pavement design and maintenance, as truck volumes influence both pavement life and design parameters (AASHTO, 2004). Roadway performance is influenced by the presence of large and/or low-performance vehicles in the traffic stream because they reduce roadway capacity (Xxxxxxx and Xxxxxx, 1983). The Highway Capacity Manual (TRB, 2000) explicitly stipulates that passenger-car equivalents of LVs under different conditions should be used for highway design. Safety is also influenced by LVs. A recent study found that 8 percent of fatal vehicle-to-vehicle crashes involved large trucks, although only 3 percent of all registered vehicles were large trucks (NHTSA, 2004). Recent studies (Xxxxxx et al., 2004; Xxx et al., 2004) also found that particulate matter (PM) is strongly associated with the onset of myocardial infarction and respiratory symptoms. Heavy duty trucks that use diesel engines are major sources of PM, accounting for 72 percent of traffic-emitted PM (EPA, 2001). All these facts illustrate that good speed and truck volume data are extremely important for accurate analysis of traffic safety, traffic pollution, and flow characteristics in transportation planning, management, and engineering. They are also important inputs for advanced traffic management systems (ATMS) and advanced traveler information systems (ATIS). Additionally, truck volume data are needed by federal and state transportation organizations to adequately monitor and analyze our nation’s freight movements. The Washington State Department of Transportation’s (WSDOT’s) dual-loop detection system classifies vehicles into fo...
RESEARCH BACKGROUND. Aside from their negative impacts on traffic safety, freeway incidents have been identified as one of the major causes for congestion. According to a Federal Highway Administration (FHWA) research report (Cambridge Systematics, Inc., 2005), approximately 50 percent of congestion on freeways is non-recurrent congestion caused by incidents (25 percent), work zones (10 percent), and bad weather (15 percent). The situation is even more severe in urban areas. Approximately one-half to two-thirds of the total travel delay in large metropolitan areas is incident-related (Center for Urban Transportation Research, 2005). Since congestion mitigation and safety enhancement are among the main goals of most transportation agencies, a number of state (and local) departments of transportation have invested in incident response (IR) programs in a variety of forms. In Washington state, the Washington State Department of Transportation (WSDOT) established its Incident Response Program in collaboration with the Washington State Patrol (WSP) and the Washington State Association of Fire Chiefs (WSAFC), a group called the Washington Traffic Incident Management Coalition (WaTIMCo). Besides prioritizing responder and motorist safety, one of WaTIMCo’s goals also involves congestion mitigation when incidents occur. Estimation of IID is highly desirable for the following reasons: • Measurement of IID is important in assessing the effectiveness of congestion countermeasures. • IID estimates help engineers understand the impacts of various types of incidents under various traffic and roadway conditions. • Accurate IID estimates can help in identifying appropriate decisions regarding IR so that limited monetary and labor resources can be allocated to maximize its benefit-to- cost ratio (BCR). • IID estimates are key components of incident cost calculations and are essential for the development of active traffic management and integrated corridor management strategies. However, it is not an easy task to quantify IID because existing traffic sensors cannot directly measure IID, and algorithms are needed to estimate IID by using available traffic sensor measurements. Therefore, IID estimation has become a hot research field. Most research efforts have been based on either Deterministic Queuing Theory (DQT) or shock wave analysis. The former calculates IID by using a queuing diagram formed by cumulative vehicle arrival and departure curves. The area enclosed by the two curves represents th...
RESEARCH BACKGROUND. From the results of previous studies, Liver Imaging Reporting and Data System (LI-RADS) on contrast-enhanced ultrasound (CEUS) for diagnosing hepatocellular carcinoma (HCC) has shown a satisfactory diagnostic value. However, a unified conclusion on the interobserver stability of this innovative ultrasound imaging has not been determined. The present meta-analysis examined the interobserver agreement of CEUS LI-RADS to provide some reference for subsequent related research. Research motivation According to the inclusion and exclusion criteria, we included eight relevant articles to explore interobserver agreement of LI-RADS on CEUS by making a meta-analysis. Finally, meta-analysis results revealed that the summary Kappa value of included studies showed substantial agreement. The heterogeneity factors included the method of enrolling patients, the method of consistency testing, and the race of patients, which should be considered in subsequent study design. Research objectives The main objective of the present article is to explore interobserver agreement of LI-RADS on CEUS for diagnosing HCC. Results of meta-analysis showed interobserver agreement is substantial and the heterogeneity factors included the method of enrolling patients, the method of consistency testing, and the race of patients, which should be considered in subsequent study design.
RESEARCH BACKGROUND. The main concepts used in the study are teacher-student relationships and emotional intelligence, which are discussed below.
RESEARCH BACKGROUND. In general, all prospective married couples before carrying out marriage are allowed to make a prenuptial agreement. This freedom is based on Article 1338 of the Civil Code (KUHPerdata).1However, when making a prenuptial agreement, there are several things that must be taken into account, namely that a prenuptial agreement must not violate or conflict with morals, public order, and must not conflict with the basics of marriage law.2 Basically, people's habits in Indonesia, when making prenuptial agreements, are usually based on several considerations. This is because some people think that a prenuptial agreement is an agreement that is projected as a weapon for women to prevent prospective husbands from committing polygamy or controlling joint property. This is different from the Dayak Ngaju tribe community with religious ceremonies, such as the marriage procedure in the Dayak Ngaju tribe community which is called "Pelek Rujin Pangawin". The marriage ceremony ritual is one of the religious rituals and is considered traditional which characterizes the existence of the Dayak Ngaju Tribe as an indigenous community group. This is because the marriage ritual does not 1 Xxxxxxxxx Xxxxxx,S.H., Kitab Undang-Undang Hukum Perdata (Jakarta: Sinar Grafika, 2010), 328. 2 Xxxxxxxxxxxx,X. Xxxxxxx, Hukum Perkawinan Di Indonesia (Bandung: Sumur, 1981)h.7 only apply to the Dayak community who adhere to the Hindu Kaharingan religion, but is also carried out by the Dayak Ngaju community who have converted to other religions. If you look closely, the marriage rituals of the Dayak Ngaju community are formed from several parts that have been patterned into one unit. This aims to reconstruct the understanding and meaning of wedding ceremonies in the aspects of tradition and religion. By understanding marriage procedures that can be considered customary and religious, it is hoped that they can return to the world of spiritual depth, subtlety of conscience and sharpness of heart as a group of people with a calm, peace-loving character in accordance with the concept of Belum Bahadat (customary living) and Huma Betang culture.3 Regarding the implementation of the Dayak Ngaju traditional marriage, it can be carried out before or after the marriage ceremony, whoever carries out the marriage, the traditional marriage procession must and must be carried out. This is intended so that in the future there will be a peaceful family, mutual love and mutual love will be maintained throughout t...
RESEARCH BACKGROUND
