scholarly journals OPTIMAL AIRLINE SEAT INVENTORY CONTROL FOR MULTI‐LEG FLIGHTS

Aviation ◽  
2004 ◽  
Vol 8 (4) ◽  
pp. 10-15
Author(s):  
Edgars K. Vasermanis ◽  
Nicholas A. Nechval ◽  
Konstantin N. Nechval ◽  
Kristine N. Rozite
Keyword(s):  
Dynamic Model ◽  
Inventory Control ◽  
Dynamic Models ◽  
Difficult Problem ◽  
Seat Allocation ◽  
The Right ◽  
Seat Inventory Control ◽  
Demand And Capacity ◽  
Over Time

Airline seat inventory control is about “selling the right seats to the right people at the right time”. In this paper, the problem of determining optimal booking policy for multiple fare classes in a pool of identical seats for multi‐leg flights is considered. During the time prior to departure of a multi‐leg flight, decisions must be made concerning the allocation of reserved seats to passengers requesting space on the full or partial spans of the flight. It will be noted that in the case of multi‐leg flights the long‐haul passengers are often unable to obtain seats because the shorter‐haul passengers block them. For large commercial airlines, efficiently setting and updating seat allocation targets for each passenger category on each multi‐leg flight is an extremely difficult problem. This paper presents static and dynamic models of airline seat inventory control for multi‐leg flights with multiple fare classes, which allow one to maximize the expected contribution to profit. The dynamic model uses the most recent demand and capacity information and allows one to allocate seats dynamically and anticipatorily over time.

A Model for Seat Allocation of Railway Passenger Transport Based on OD’s Priority

2014 ◽  
Vol 989-994 ◽  
pp. 2344-2348 ◽  
Author(s):  
Ying Ting Zhu ◽  
Fu Zhang Wang ◽  
Xing Hua Shan ◽  
Xiao Yan Lv
Keyword(s):  
Revenue Management ◽  
Inventory Control ◽  
Optimization Model ◽  
Control Method ◽  
Optimization Strategy ◽  
Passenger Transport ◽  
Railway Passenger Transport ◽  
Seat Allocation ◽  
Railway Passenger ◽  
Seat Inventory Control

Based on the seat inventory control method of revenue management in airline, the author researches the optimization strategy on the seat inventory control in railway passenger transport. The author proposes one optimization model for seats allocation, which is to allocate seats by calculating the value to determine the order of getting seats for each OD under the analysis of the interaction among all trains running on the same rail lines and those trains’ demands intensity. The experiment results show that this new model can be used to allocate seats for the train with multiple stations rapidly and appropriately. In comparison with the method without considering the value of each OD, the model based on OD’s value can get better results.

Forecasting Interconnections in International Housing Markets: Evidence from the Dynamic Model Averaging Approach

2020 ◽  
Vol 42 (1) ◽  
pp. 37-103
Author(s):  
Hardik A. Marfatia
Keyword(s):  
Dynamic Model ◽  
Model Averaging ◽  
Housing Markets ◽  
The United States ◽  
Forecasting Model ◽  
Change Over Time ◽  
The United Kingdom ◽  
Novel Approach ◽  
Dynamic Model Averaging ◽  
Over Time

In this paper, I undertake a novel approach to uncover the forecasting interconnections in the international housing markets. Using a dynamic model averaging framework that allows both the coefficients and the entire forecasting model to dynamically change over time, I uncover the intertwined forecasting relationships in 23 leading international housing markets. The evidence suggests significant forecasting interconnections in these markets. However, no country holds a constant forecasting advantage, including the United States and the United Kingdom, although the U.S. housing market's predictive power has increased over time. Evidence also suggests that allowing the forecasting model to change is more important than allowing the coefficients to change over time.

Improvement in prefrontal thalamic connectivity during the early course of the illness in recent-onset psychosis: a 12-month longitudinal follow-up resting-state fMRI study

2020 ◽  
pp. 1-9
Author(s):  
Daniel Bergé ◽  
Tyler A. Lesh ◽  
Jason Smucny ◽  
Cameron S. Carter
Keyword(s):  
Resting State ◽  
Resting State Fmri ◽  
Functional Changes ◽  
Recent Onset ◽  
Fmri Study ◽  
Clinical Meaning ◽  
Mixed Pattern ◽  
The Right ◽  
Over Time

Abstract Background Previous research in resting-state functional magnetic resonance imaging (rs-fMRI) has shown a mixed pattern of disrupted thalamocortical connectivity in psychosis. The clinical meaning of these findings and their stability over time remains unclear. We aimed to study thalamocortical connectivity longitudinally over a 1-year period in participants with recent-onset psychosis. Methods To this purpose, 129 individuals with recent-onset psychosis and 87 controls were clinically evaluated and scanned using rs-fMRI. Among them, 43 patients and 40 controls were re-scanned and re-evaluated 12 months later. Functional connectivity between the thalamus and the rest of the brain was calculated using a seed to voxel approach, and then compared between groups and correlated with clinical features cross-sectionally and longitudinally. Results At baseline, participants with recent-onset psychosis showed increased connectivity (compared to controls) between the thalamus and somatosensory and temporal regions (k = 653, T = 5.712), as well as decreased connectivity between the thalamus and left cerebellum and right prefrontal cortex (PFC; k = 201, T = −4.700). Longitudinal analyses revealed increased connectivity over time in recent-onset psychosis (relative to controls) in the right middle frontal gyrus. Conclusions Our results support the concept of abnormal thalamic connectivity as a core feature in psychosis. In agreement with a non-degenerative model of illness in which functional changes occur early in development and do not deteriorate over time, no evidence of progressive deterioration of connectivity during early psychosis was observed. Indeed, regionally increased connectivity between thalamus and PFC was observed.

scholarly journals Radiation-Induced Metabolic Shifts in the Hepatic Parenchyma: Findings from 18F-FDG PET Imaging and Tissue NMR Metabolomics in a Mouse Model for Hepatocellular Carcinoma

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2573
Author(s):  
Yi-Hsiu Chung ◽  
Cheng-Kun Tsai ◽  
Ching-Fang Yu ◽  
Wan-Ling Wang ◽  
Chung-Lin Yang ◽  
...  
Keyword(s):  
Fdg Pet ◽  
Liver Parenchyma ◽  
Metabolic Alterations ◽  
Nmr Metabolomics ◽  
Post Irradiation ◽  
The Third ◽  
Radiation Induced ◽  
18F Fdg ◽  
The Right ◽  
Over Time

Purpose: By taking advantage of 18F-FDG PET imaging and tissue nuclear magnetic resonance (NMR) metabolomics, we examined the dynamic metabolic alterations induced by liver irradiation in a mouse model for hepatocellular carcinoma (HCC). Methods: After orthotopic implantation with the mouse liver cancer BNL cells in the right hepatic lobe, animals were divided into two experimental groups. The first received irradiation (RT) at 15 Gy, while the second (no-RT) did not. Intergroup comparisons over time were performed, in terms of 18F-FDG PET findings, NMR metabolomics results, and the expression of genes involved in inflammation and glucose metabolism. Results: As of day one post-irradiation, mice in the RT group showed an increased 18F-FDG uptake in the right liver parenchyma compared with the no-RT group. However, the difference reached statistical significance only on the third post-irradiation day. NMR metabolomics revealed that glucose concentrations peaked on day one post-irradiation both, in the right and left lobes—the latter reflecting a bystander effect. Increased pyruvate and glutamate levels were also evident in the right liver on the third post-irradiation day. The expression levels of the glucose-6-phosphatase (G6PC) and fructose-1, 6-bisphosphatase 1 (FBP1) genes were down-regulated on the first and third post-irradiation days, respectively. Therefore, liver irradiation was associated with a metabolic shift from an impaired gluconeogenesis to an enhanced glycolysis from the first to the third post-irradiation day. Conclusion: Radiation-induced metabolic alterations in the liver parenchyma occur as early as the first post-irradiation day and show dynamic changes over time.

Explaining the Epigraphic Habit in the Roman Empire: The Evidence of Epitaphs

1990 ◽  
Vol 80 ◽  
pp. 74-96 ◽  
Author(s):  
Elizabeth A. Meyer
Keyword(s):  
Roman Empire ◽  
North Africa ◽  
Legal Status ◽  
The Third ◽  
The Right ◽  
Political Economic ◽  
Over Time

It is now notorious that the production of inscriptions in the Roman Empire was not constant over time, but rose over the first and second centuries A.D. and fell in the third. Ramsay MacMullen pointed this out more than five years ago, with conclusions more cautionary than explanatory: ‘history is not being written in the right way’, he said, for historians have deduced Rome's decline from evidence that–since it appears only epigraphically–has merely disappeared for its own reasons, or have sought general explanations of decline in theories political, economic, or even demographic in nature, none of which can, in turn, explain the disappearance of epigraphy itself. Why this epigraphic habit rose and fell MacMullen left open to question, although he did postulate control by a ‘sense of audience’. The purpose of this paper is to propose that this ‘sense of audience’ was not generalized or generic, but depended on a belief in the value of romanization, of which (as noted but not explained by MacMullen's article) the epigraphic habit is also a rough indicator. Epitaphs constitute the bulk of all provincial inscriptions and in form and number are (generally speaking) the consequence of a provincial imitation of characteristically Roman practices, an imitation that depended on the belief that Roman legal status and style were important, and that may indeed have ultimately depended, at least in North Africa, on the acquisition or prior possession of that status. Such status-based motivations for erecting an epitaph help to explain not only the chronological distribution of epitaphs but also the differences in the type and distribution of epitaphs in the western and eastern halves of the empire. They will be used here moreover to suggest an explanation for the epigraphic habit as a whole.

The right to the night sky in punitive enclosure context

2019 ◽  
Vol 15 (S367) ◽  
pp. 402-403
Author(s):  
Natalia Guevara ◽  
Rodrigo F. Haack ◽  
Victoria B. Acosta ◽  
María A. Senn ◽  
Carolina A. Silva ◽  
...  
Keyword(s):  
Social Work ◽  
Social Communication ◽  
Juvenile Detention ◽  
Educational Science ◽  
La Plata ◽  
Detention Centers ◽  
National University ◽  
Night Sky ◽  
The Right ◽  
Over Time

AbstractThe “Right to the night sky” outreach project holds astronomy workshops for children and teens deprived of their liberty in juvenile detention centers. It is carried out by an interdisciplinary group of students, graduates, and teachers of Astronomy, Geophysics, Educational Science, Law, Psychology, Social Work, and Social Communication. It’s has been accredited and recognized by the Faculty of Astronomical and Geophysical Sciences, and the National University of La Plata (Argentina) since the year 2014. This work presents the diverse activities developed in the project, the methodologies used, and an analysis of how the project evolved, grew, and expanded over time, continuing what has already been presented by Charalambous et al. (2014) and Haack et al. (2019)

Research on mechanism configuration and dynamic characteristics for multi-split transmission line mobile robot

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wei Jiang ◽  
Yating Shi ◽  
Dehua Zou ◽  
Hongwei Zhang ◽  
Hong Jun Li
Keyword(s):  
Mobile Robot ◽  
Transmission Line ◽  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Transmission Lines ◽  
Dynamic Models ◽  
Working Environment ◽  
Joint Torque ◽  
Content Type ◽  
Working Space

Purpose The purpose of this paper is to achieve the optimal system design of a four-wheel mobile robot on transmission line maintenance, as the authors know transmission line mobile robot is a kind of special robot which runs on high-voltage cable to replace or assist manual power maintenance operation. In the process of live working, the manipulator, working end effector and the working environment are located in the narrow space and with heterogeneous shapes, the robot collision-free obstacle avoidance movement is the premise to complete the operation task. In the simultaneous operation, the mechanical properties between the manipulator effector and the operation object are the key to improve the operation reliability. These put forward higher requirements for the mechanical configuration and dynamic characteristics of the robot, and this is the purpose of the manuscript. Design/methodology/approach Based on the above, aiming at the task of tightening the tension clamp for the four-split transmission lines, the paper proposed a four-wheel mobile robot mechanism configuration and its terminal tool which can adapt to the walking and operation on multi-split transmission lines. In the study, the dynamic models of the rigid robot and flexible transmission line are established, respectively, and the dynamic model of rigid-flexible coupling system is established on this basis, the working space and dynamic characteristics of the robot have been simulated in ADAMS and MATLAB. Findings The research results show that the mechanical configuration of this robot can complete the tightening operation of the four-split tension clamp bolts and the motion of robot each joint meets the requirements of driving torque in the operation process, which avoids the operation failure of the robot system caused by the insufficient or excessive driving force of the robot joint torque. Originality/value Finally, the engineering practicability of the mechanical configuration and dynamic model proposed in the paper has been verified by the physical prototype. The originality value of the research is that it has double important theoretical significance and practical application value for the optimization of mechanical structure parameters and electrical control parameters of transmission line mobile robots.

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