Regular Route Research Articles

Improving routing and scheduling decisions at a distributor of industrial gasses

This paper investigates cyclical inventory replenishment for a company's regional distribution center that supplies, distributes, and manages inventory of carbon dioxide ( CO 2 ) at over 900 separate customer sites in Indiana. The company previously experienced high labor costs with excessive overtime and maintained a regular back-log of customers experiencing stockouts. To address these issues we implemented a three-phase heuristic for the cyclical inventory routing problem encountered at one of the company's distribution centers. This heuristic determines regular routes for each of three available delivery vehicles over a 12-day delivery horizon while improving four primary performance measures: delivery labor cost, stockouts, delivery regularity, and driver–customer familiarity. It does so by first determining three sets of cities (one for each delivery vehicle) that must be delivered to each day based on customer requirements. Second, the heuristic assigns the remaining customers in other cities to one of the three “backbone routes” determined in phase 1. And third, it balances customer deliveries on each daily route over the schedule horizon. Through our methodology, we were able to significantly reduce overtime, driving time, and labor costs while improving customer service.

A Morning Stroll

Walking as part of the commute has been suggested as a source of healthful moderate activity, although there has been little empirical study to verify this supposition or determine whether one mode is superior to others. This cross-sectional study assessed differences between car and train commuters in level of physical activity. One hundred eleven train and car commuters were asked to wear a pedometer for one week of commuting on their regular route plus complete a standardized self-report physical activity index. Train commuters walked an average of 30% more steps per day, reported having walked for a period of 10 minutes or more while traveling significantly more often, and were 4 times more likely to walk 10,000 steps per day than car commuters. Transportation mode can significantly affect the amount of physical activity commuters accumulate during the course of a typical work day without planned or coordinated exercise programs.

Horizontal stent placement plus coiling in a broad-based basilar-tip aneurysm: an alternative to the Y-stent technique

Basilar tip aneurysms are the most frequent type of aneurysm in the posterior circulation. Specifically, if wide-necked, they remain a significant therapeutic challenge. On the endovascular side, stents may help to overcome many of these technical challenges. However, if both P1 segments encroach into the aneurysm neck, sometimes stent placement from the middle of the basilar artery to one P1 segment is not enough. Therefore, some groups recommend the use of the so-called Y-stent technique, with one stent passing through the interstices of another stent in a Y-configuration thus remodelling the basilar tip. We describe a patient with a broad-based basilar tip aneurysm and a single, very tortuous vertebral artery which did not allow the use of the vertebrobasilar system as the straight route to the aneurysm. Because of the well-known high surgical risk we decided to navigate the stent through the internal carotid artery and via the posterior communicating artery into the contralateral P1 segment and placed the stent at right angles to the aneurysm from one P1 segment to the contralateral one. The outcome in the patients was excellent without any ischemic lesions. Horizontal stent placement in wide-necked basilar tip aneurysms may be a therapeutic alternative if the regular route via the vertebral arteries is not feasible.

Phytoplankton community dynamics assessed by ships-of-opportunity sampling in the northern Baltic Sea: A comparison of HPLC pigment analysis and cell counts

The dynamics of phytoplankton diversity constitute crucial data in environmental monitoring, food-web studies and ecosystem modeling. Proper assessment of phytoplankton community composition requires large investments in offshore sampling and taxonomic competence because these communities can change fundamentally on a weekly scale. Cheap and high-frequent offshore phytoplankton sampling can be achieved by using ships-of-opportunity, and in the present study we used the Alg@line facilities onboard a passenger ferry during its regular route between Finland and Sweden in the northern Baltic Sea. The first aim was to test if pigment analysis, as a cheaper alternative to cell counts, can be used to detect environment-correlated variation in phytoplankton communities. It has been shown that spatial variation (salinity differences) and variation throughout one annual cycle (changes in temperature and nutrients) were strongly reflected by pigment composition. The second aim was to test if pigment analyses and cell counts detect environment-correlated variation in phytoplankton communities equally well. It has been shown that spatial and seasonal variations were reflected by pigment composition while cell counts reflected seasonal variation only. This suggests that the pigment analyses detected aspects of the phytoplankton that were neglected or misinterpreted by cell counts. It is advocated that available resources of long-term studies, such as environmental monitoring, can be used more efficiently by utilizing the high ecological resolution of pigment composition in combination with high-frequent ships-of-opportunity sampling. To assess heterotrophic and/or toxic species, such programs could also include sampling for cell counts in a complementary manner, with actually performing counts only for crucial samples (e.g. between large community changes) as indicated by multivariate statistical analysis of pigment composition. Some aspects of analyzing phytoplankton data with multivariate statistics are also discussed.

AHP를 이용한 낙도 보조항로 운영주체 선정에 관한 실증연구

최근 낙도 보조항로의 운영에 있어서 선박 취항명령후 운영사업자의 계속적인 사업수행으로 일반항로에 비해 경영개선노력이 부진하거나 서비스의 질이 저하되는 등 여러 가지 문제점이 나타나고 있다. 따라서 본 연구에서는 낙도 보조항로 운영주체를 검토하여 개선방향을 제시하고자 AHP 기법을 이용한 실증연구를 수행하였다. 연구결과 보조항의 사업자에 대한 경영평가제를 도입하여 사업자 스스로 지속적인 경영개선 노력을 유도함이 바람직할 것으로 보인다. A range of problems have risen as the results of the obligated charter service. Constant lack of operation improvement compared to regular routes and lower quality service are results of business practice by the service providers. Therefore, this study executed an empirical research using AHP to present a method for improvement by investigating remote island charter service providers. Result shows that the desirable method is to implement operation evaluation system to induce service providers to consistently put efforts on the operating system development.

Sensors for Detection of Misbehaving Nodes in MANETs

Sensors for Detection of Misbehaving Nodes in MANETs

Analysis of Delivery Activities of Trucks Using Probe Car Data

This study aims to analyze delivery activities of freight trucks by using probe car data including drivers' working status and obtain the basic informationeeded for solving the vehicle routing and scheduling problems.Two truck companies of different operations were studied, one which mainly hauls goods over medium-to-long distances and the other which hauls goods along regular routes to locations inside the city.The following information was revealed through the analysis; 1.Fluctuation of travel speeds, 2.Distribution of arrival times to destination facilities, 3.Distnbution of loading and unloading times and 4.Behavioral patterns of keeping the designated time windows.

Variability of the sea surface salinity (SSS) in the western tropical Pacific: On the ability of an OGCM to simulate the SSS, and on the sampling of an operating merchant ship SSS network

The sea surface salinity (SSS) derived from a network developed at Institut de Recherche pour le Developpement (IRD/Noumea) has been analyzed during the period 1995–1998 in the tropical western Pacific. The measurements were made with thermosalinographs installed on merchant ships selected for their regularity and routes. The western tropical Pacific was sampled mainly along three regular routes across the equator leading to an average of a one month frequency. We analyze here how such a network can be efficient in monitoring the SSS at time scales longer than one month. For this purpose we have used results derived from the Princeton Ocean Model (POM) which is forced by the surface flux of National Centers for Environmental Prediction (NCEP) reanalysis data. The interannual variability of the simulated SSS exhibits very similar features to (sub-sampled) observations despite its being weakly damped to a climatology in order to avoid biases. Even smaller time scale phenomena can be simulated, like the erosion/reconstruction of the region composed of low density waters lying within the Pacific warm pool. The agreement between the observational data and the simulations indicate that the network sampling is sufficient to monitor the SSS variability of the western tropical Pacific from three-month to interannual time scales.

SOME APPROACHES ON CHECKPOINT DIAL-A-RIDE PROBLEMS

Within advanced public transport operations, specifically paratransit systems, a special range is covered by the so-called checkpoint dial-a-ride systems, also known as route deviation or corridor many-to-one systems. The system combines characteristics both of traditional fixed route transit and of advanced door-to-door dial-a-ride service. Such systems are based on information technology to improve transit operations and are intended to serve areas with demand densities too high for door-to-door services but not high enough for fixed route service. The paper presents some recent mathematical modelling approaches to the deviation bus route operations which accept user demands and makes the bus deviate from its regular route to serve the off-fixed-route request and then return on the regular route.

A mathematical programming model for the bus deviation route problem

In small towns, or in those peripherical metropolitan areas in which the demand for public transportation is relatively low, the objectives of the bus route planner are different from those faced in highly congested networks. Some towns, also in Italy, are experimenting with urban public transportation systems where regular bus routes are designed which allow users located at specific points outside the main line to signal their presence to the bus driver, who then deviates from the main route to satisfy this demand. This way the bus line is a mixture between a regular line and a dial-a-ride system. The bus deviation route problem is concerned with the design problem which arises in planning the location of the demand points outside the line. A model is presented which takes into account both the advantage of passengers served by this deviation device and the disadvantage suffered by passengers on the bus, whose travel time increases during deviations, and by passengers downstream of the deviation whose waiting time also increases. Through some modeling assumption we are able to represent this problem as a mixed integer linear programming problem, whose relatively low dimension allows for exact solution through standard simplex-based branch and bound code. The proposed model has been applied to a real case and some results of this are presented and discussed.

Complexity of routes to chaos and global regularity of fractal dimensions in bimodal maps

The dual-star composition rule of doubly superstable (DSS) sequences presents a complete renormalizable algebraic structure for studying Feigenbaum's metric universality and self-similar classification of DSS sequences in symbolic dynamics of bimodal maps of the interval. Here an important feature is that the complete combinations of up- and down-star products create all the generalized Feigenbaum's routes of transitions to chaos. These routes can be classified into two types: one consists of countably infinitely many regular routes which preserve Feigenbaum's metric universality; another consists of uncountably infinitely many universal nonscaling routes described by the irregularly mixed dual-star products, which break Feigenbaum's asymptotically convergent metric universality although they are structurally universal. The combinatorial complexity of dual-star products may increase the grammatical complexity of languages of symbolic dynamics. Moreover, it is found that there exists a global regularity between the fractal dimensions d and the scaling factors [alpha(C),alpha(D)] for Feigenbaum-type attractors: d(Z)log(/Z/)/alpha(C)(Z)alpha(D)(Z)/=beta((2)), where beta((2)) is independent of the concrete DSS sequences Z.

Dahomey's Royal Road

Nineteenth-century European visitors to the kingdom of Dahomey were not easily impressed, certainly not by any infrastructural refinement. So when one after another perceived grandeur in the Cana-Abomey road, it was no small compliment. For French travelers the road was “magnifique,” “superbe,” a “merveille,” “fort belle,” “vraiment belle,” or “des plus belles.” For British travelers “splendid” or—perhaps the ultimate accolade—as broad as any thoroughfare in England.This remarkable road was the last leg of the regular route from Dahomey's Atlantic port of Whydah to the royal capital at Abomey. Its basic purpose was not to impress foreigners on their approach to the capital, as one might imagine, but to allow the kings of Dahomey to travel to and from Cana in style.In Fon traditions Cana dates back to the origins of the kingdom in the early seventeenth century and may have preceded Abomey as tribalchef-lieu. When Dahomey was subject to the Yoruba empire of Oyo (from the 1730s or 1740s to the 1820s), Cana was the place where Oyo messengers collected the annual tribute. King Gezo (1818-58) is said to have begun his successful challenge of Oyo very early in his reign by having those messengers slaughtered.

Acquisition of a deliberately introduced phenol degradation operon, pheBA, by different indigenous Pseudomonas species.

Horizontal transfer of genes of selective value in an environment 6 years after their introduction into a watershed has been observed. Expression of the gene pheA, which encodes phenol monooxygenase and is linked to the pheBA operon (A. Nurk, L. Kasak, and M. Kivisaar, Gene 102:13-18, 1991), allows pseudomonads to use phenol as a growth substrate. Pseudomonas putida strains carrying this operon on a plasmid were used for bioremediation after an accidental fire in the Estonia oil shale mine in Estonia in 1988. The water samples used for studying the fate of the genes introduced were collected in 1994. The same gene cluster was also detected in Pseudomonas strains isolated from water samples of a nearby watershed which has been continuously polluted with phenols due to oil shale industry leachate. Together with the more frequently existing counterparts of the dmp genes (V. Shingler, J. Powlowski, and U. Marklund, J. Bacteriol. 174:711-724, 1992), the pheA gene was also represented in the phenol-degrading strains. The area where the strains containing the pheA gene were found was restricted to the regular route of phenolic leachate to the Baltic Sea. Nine Pseudomonas strains belonging to four different species (P. corrugata, P. fragi, P. stutzeri, and P. fluorescens biotypes B, C, and F) and harboring horizontally transferred pheBA operons were investigated. The phe genes were clustered in the same manner in these nine phe operons and were connected to the same promoter as in the case of the original pheBA operon. One 10.6-kb plasmid carrying a pheBA gene cluster was sequenced, and the structure of the rearranged pheBA operon was described. This data indicates that introduced genetic material could, if it encodes a beneficial capability, enrich the natural genetic variety for biodegradation.

A merchant ship thermo-salinograph network in the Pacific Ocean

The need for better knowledge of sea surface salinity (SSS) and sea surface temperature (SST) distribution in the tropical oceans was brought to light during the 10 years of the TOGA programme (1985–1994). In order to improve on the original “meteorological bucket” method of sampling, we developed a network of merchant ships among those operating regular routes through the tropical Pacific, and equipped them with thermo-salinographs. Accurate positioning of the ships was obtained using a satellite positioning system. High frequency sampling (every 15 s) and recording of the median values for every 5 min resulted in quite precise monitoring of the SST and SSS, and in a description of the salinity fronts along the routes followed by the ships. Using this equipment, we were able to detect the influence of local rainfall on salinity and temperature and the diurnal cycle of sea surface temperature. The accuracy of salinity measurements (0.02) was better than that of the old sampling technique by one order of magnitude. Temperature measurement by the thermo-salinograph was very stable but yielded results that are 0.2–0.3°C higher than sea surface temperature. To ensure reliability of data, the equipment was carefully checked every time the ships called at Noumea (i.e. every 2–3 months), and re-calibration every year or two is essential.

What's Happening to Photography?

AbstractThis is the first public output of the joint Arts Council/University of Portsmouth research project into photography teaching in GNVQ Art and Design and Media Communications and Production. It reports principally from various contacts and interviews in the first six months of the project and from the results of a questionnaire survey of art and design lecturers involved in GNVQ.The paper suggests that the increasing significance of photography in artistic cultural and social practices is not adequately reflected in formal education. It describes a variety of aims and practices in those institutions involved in GNYQ, although we have found little collaboration between art and design and media courses. In some art and design courses, photography functions mainly as an aid to research and preparatory work, elsewhere we found lecturers willing to describe it as ‘an art form in its own right’ or as a ‘fundamental part’ of the art and design curriculum.We report on the resource implications of offering substantial photography courses. some preliminary findings about the kinds of students studying art and design GNVQ, and the perceived value of official publications. The question of choosing ‘A’ level or GNVQ is raised, as is the issue of progression. We have found expectations that GNVQs will become a regular route into HE although their currency is not yet clear.Although we report difficulties with GNVQs in art and design, and more specifically with photography, we also record comments which indicate some reasons for optimism.

Schedule-induced hours-of-service and speed limit violations among tractor-trailer drivers

Driver fatigue is well recognized as an important causational factor in accidents involving long-distance truck drivers. Drivers may drive while fatigued for a variety of reasons. Important among these is the assignment of difficult or unreasonable delivery schedules. Using self-reported data, the frequency of violation-inducing schedules is estimated during their ongoing movement for a sample of 498 long-distance drivers. Assuming average legal speed limits of 55 mph, 26% of the drivers were found to have violation-inducing schedules. Solo drivers, drivers hauling refrigerated loads, regular route drivers, and those with longer current trip distances are the most likely to have such schedules. Also estimated were total weekly work hours. Assuming average attained travelling speeds of 50 mph, the average driver drives 46 hours per week and works a total of 58 hours.

Stated preferences for investigating commuters' diversion propensity

A reasonable response to increasing traffic congestion may come from the rapidly developing traveler information systems. Such systems may be successful if they effectively influence drivers' enroute decisions; in this regard, a critical factor may be commuters' willingness to divert from their regular route in response to information about traffic congestion. This study evaluates the effects of real-time traffic information along with driver attributes, roadway characteristics and situational factors on drivers' willingness to divert. The empirical portion of this study is based on a survey of downtown Chicago automobile commuters. The stated preference approach was used to study commuters' diversion propensity. Drivers expressed a higher willingness to divert if expected delays on their usual route increased, if the congestion was incident-induced as opposed to recurring, if delay information was received from radio traffic reports compared with observing congestion, and if trip direction was home-to-work rather than work-to-home. Respondents were less willing to divert if their alternate route was unfamiliar, unsafe or had several traffic stops. Socioeconomic characteristics were also significant in predicting willingness to divert.

Commuters' enroute diversion and return decisions: Analysis and implications for advanced traveler information systems

Incident-induced congestion is a major source of delay and frustration for drivers in large urban areas. Advanced Traveler Information Systems (ATIS) have been proposed within the framework of Intelligent Vehicle Highway Systems (IVHS) to address one component of the incident-induced congestion problem: diversion of drivers to alternate routes. To fully utilize the potential of ATIS, transportation managers need to understand driver response to such congestion. This study examines short-term commuter response to unexpected (incident-induced) congestion. It investigates factors which influence diversion from the regular route and return to the regular route after diversion. Discrete choice models of diversion and return behavior show that the following information and trip factors increase the probability of diversion: delay information received from radio traffic reports as opposed to observation of congestion, longer delays and longer travel times, and number of alternate routes used in the past. Further, drivers were more likely to divert if they lived in the city as opposed to the suburbs, were risk seekers, had a higher stated propensity to divert and were male. However, anticipated congestion on the alternate route inhibited drivers from diverting. Finally, drivers who had longer commute trips were more likely to return to their regular route. The most important implication for designing ATIS is that traffic information must be “customized” to account for individual differences. Specific design implications are discussed in this paper.

An Orientation and Mobility Approach to Problems of a Neurologically Impaired Adult

A San Francisco woman with no visual impairment but a neurological processing deficit has been helped through O&M training. She is completely unable to process spatial relationships, and this has resulted in difficulties in travel and problems at work and school. Applying Orientation and Mobility methods helped her cope with street crossings, perform simple household tasks, and locate specific rooms within buildings. Techniques used included “hands-on” guidance; taping lessons and direction so they could be reviewed; memorizing essential information; and using an index-card system to “signpost” regular routes.

Movements of groups of tui (Prosthemadera novaeseelandiae) in winter and settlement of juvenile tui in summer

Abstract An individually colour-banded population of tui (Meliphagidae) was studied and individuals were shown to move over sometimes large distances in search of nectar during most of the year. However, individuals were localised into small foraging areas when nectar was abundant during summer breeding. Tui forage a regular route, taking their newly independent young with them through winter. These family groups sometimes consist of previous years' young and also other adults. These same group members nest near each other during summer and their offspring establish nesting areas nearby in following years.