Designing Customised Bus Routes for Urban Commuters with the Existence of Multimodal Network – A Bi-Level Programming Approach

Customised bus (CB) is a cutting-edge mean of transportation and has been implemented worldwide. To support the spread of the CB system, methodologies for CB network design have been conducted. However, a majority of them cannot be adopted directly for multi-modal transportation environment. In this paper, we proposed a bi-level programming model to fill this gap. The upper-level problem is to maximise the usage of the CB system with the limitation of operation constraints. Meanwhile, the lower-level problem is to capture the traveller’s choice by minimising traveller’s generalised cost during travel. A solving procedure via genetic algorithm is further proposed and validated via the metro data at Shanghai. The results indicated that the proposed CB route network would attract nearly 5,000 users during morning peak period under the given metro transaction data. We further studied the features of the selected routes and found that the CB network mainly served residence to commercial or industrial parks travellers and would provide travel service with fewer stops, and higher travel efficiency by travelling through expressway

GNNFlow: A Distributed Framework for Continuous Temporal GNN Learning on Dynamic Graphs

Graph Neural Networks (GNNs) play a crucial role in various fields. However, most existing deep graph learning frameworks assume pre-stored static graphs and do not support training on graph streams. In contrast, many real-world graphs are dynamic and contain time domain information. We introduce GNNFlow, a distributed framework that enables efficient continuous temporal graph representation learning on dynamic graphs on multi-GPU machines. GNNFlow introduces an adaptive time-indexed block-based data structure that effectively balances memory usage with graph update and sampling operation efficiency. It features a hybrid GPU-CPU graph data placement for rapid GPU-based temporal neighborhood sampling and kernel optimizations for enhanced sampling processes. A dynamic GPU cache for node and edge features is developed to maximize cache hit rates through reuse and restoration strategies. GNNFlow supports distributed training across multiple machines with static scheduling to ensure load balance. We implement GNNFlow based on DGL and PyTorch. Our experimental results show that GNNFlow provides up to 21.1x faster continuous learning than existing systems

Contrastive analysis of distractions to pilot caused by various flight instrument displays

Automation of aircraft instrument displays enhances flight safety, but it also increases complexity and pilot workload. Executing changes in flight plan, navigation or communication during flight using flight instrument switches often increases pilots’ workload and this may also cause distraction that adds potential risks to flight safety. This study compares the conventional avionics panel and touchscreen avionic panel to find out the least distractive panel for the pilots. Thirty simulated flights using four different pilots were carried out; and aircraft speed, altitude and heading parameters using both avionics systems were observed to study the operational efficiency and pilot distraction resulted from each of the avionic systems. The distraction was examined by a parameter analysis based on the Mean Squared Error (MSE) mathematical model and visually by recording videos of each simulated flight. The results indicate that the touchscreen system is more efficient and less erroneous for the aircraft in maintaining the parameters as compared with the conventional system. There is also a clear relationship between task completion time and disruption level on the parameters control

Identification of drought-responsive microRNAs in Medicago truncatula by genome-wide high-throughput sequencing

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) are small, endogenous RNAs that play important regulatory roles in development and stress response in plants by negatively affecting gene expression post-transcriptionally. Identification of miRNAs at the global genome-level by high-throughout sequencing is essential to functionally characterize miRNAs in plants. Drought is one of the common environmental stresses limiting plant growth and development. To understand the role of miRNAs in response of plants to drought stress, drought-responsive miRNAs were identified by high-throughput sequencing in a legume model plant, <it>Medicago truncatula</it>.</p> <p>Results</p> <p>Two hundreds eighty three and 293 known miRNAs were identified from the control and drought stress libraries, respectively. In addition, 238 potential candidate miRNAs were identified, and among them 14 new miRNAs and 15 new members of known miRNA families whose complementary miRNA*s were also detected. Both high-throughput sequencing and RT-qPCR confirmed that 22 members of 4 miRNA families were up-regulated and 10 members of 6 miRNA families were down-regulated in response to drought stress. Among the 29 new miRNAs/new members of known miRNA families, 8 miRNAs were responsive to drought stress with both 4 miRNAs being up- and down-regulated, respectively. The known and predicted targets of the drought-responsive miRNAs were found to be involved in diverse cellular processes in plants, including development, transcription, protein degradation, detoxification, nutrient status and cross adaptation.</p> <p>Conclusions</p> <p>We identified 32 known members of 10 miRNA families and 8 new miRNAs/new members of known miRNA families that were responsive to drought stress by high-throughput sequencing of small RNAs from <it>M. truncatula</it>. These findings are of importance for our understanding of the roles played by miRNAs in response of plants to abiotic stress in general and drought stress in particular.</p

Plant 3D Chromatin Organization: Important Insights from Chromosome Conformation Capture Analyses of the Last 10 Years

Over the past few decades, eukaryotic linear genomes and epigenomes have been widely and extensively studied for understanding gene expression regulation. More recently, the three-dimensional (3D) chromatin organization was found to be important for determining genome functionality, finely tuning physiological processes for appropriate cellular responses. With the development of visualization techniques and chromatin conformation capture (3C)-based techniques, increasing evidence indicates that chromosomal architecture characteristics and chromatin domains with different epigenetic modifications in the nucleus are correlated with transcriptional activities. Subsequent studies have further explored the intricate interplay between 3D genome organization and the function of interacting regions. In this review, we summarize spatial distribution patterns of chromatin, including chromatin positioning, configurations and domains, with a particular focus on the effect of a unique form of interaction between varieties of factors that shape the 3D genome conformation in plants. We further discuss the methods, advantages and limitations of various 3C-based techniques, highlighting the applications of these technologies in plants to identify chromatin domains, and address their dynamic changes and functional implications in evolution, and adaptation to development and changing environmental conditions. Moreover, the future implications and emerging research directions of 3D genome organization are discussed

Elevated ozone decreases the multifunctionality of belowground ecosystems

Elevated tropospheric ozone (O-3) affects the allocation of biomass aboveground and belowground and influences terrestrial ecosystem functions. However, how belowground functions respond to elevated O-3 concentrations ([O-3]) remains unclear at the global scale. Here, we conducted a detailed synthesis of belowground functioning responses to elevated [O-3] by performing a meta-analysis of 2395 paired observations from 222 publications. We found that elevated [O-3] significantly reduced the primary productivity of roots by 19.8%, 16.3%, and 26.9% for crops, trees and grasses, respectively. Elevated [O-3] strongly decreased the root/shoot ratio by 11.3% for crops and by 4.9% for trees, which indicated that roots were highly sensitive to O-3. Elevated [O-3] impacted carbon and nitrogen cycling in croplands, as evidenced by decreased dissolved organic carbon, microbial biomass carbon, total soil nitrogen, ammonium nitrogen, microbial biomass nitrogen, and nitrification rates in association with increased nitrate nitrogen and denitrification rates. Elevated [O-3] significantly decreased fungal phospholipid fatty acids in croplands, which suggested that O-3 altered the microbial community and composition. The responses of belowground functions to elevated [O-3] were modified by experimental methods, root environments, and additional global change factors. Therefore, these factors should be considered to avoid the underestimation or overestimation of the impacts of elevated [O-3] on belowground functioning. The significant negative relationships between O-3-treated intensity and the multifunctionality index for croplands, forests, and grasslands implied that elevated [O-3] decreases belowground ecosystem multifunctionality

The Research of Hedging Strategies for Longevity Risk

[[abstract]]在世界各個已開發國家，因醫療水準之普及，使得人類平均餘命上昇，導致浮現出人口老化所引起的勞動力不足，社會福利支出大幅增加等社會經濟問題，例如在台灣的勞保、健保等退休、醫療有關的社會保險面臨可能的虧損經營；壽險公司也因死亡率改善及低利率的雙重影響，造成年金商品恐發生保費短收的問題。為了規避長壽風險帶來之損失，保險公司可選擇將不確定性風險轉移至資本市場，由投資人協助分攤。因此，死亡率風險證劵化之相關衍生性商品因應而生。 王信忠、余清祥(2011)探討長壽債券的設計以轉移死亡率改善之風險，在設定債券給付架構時，死亡率改善模型的選擇相當重要。因此本文將分別站在保險人立場衡量避險策略之成本花費，與投資人購買死亡率債券商品的可行性，藉由隨機死亡率Lee-Carter模型及Renshaw-Haberman A-P-C模型產生不同死亡率情境，模擬實際可能發生之情況，探討保險公司與投資人利用避險費用效益的衡量指標，選擇不同避險策略如風險自留、再保險與長壽債券等所帶來的影響。本文可以提供保險公司面對長壽風險時考量避險策略時之參考。 Due to the healthcare quality improved in the developed countries, people's life expectancy has been increasing. The aging population has caused an increasing social welfare expense and labor shortages. The double effects of the mortality improvement and lower interest rates are the reasons resulting in the shorten reserve of insurance companies. So, it is a very important thing for the insurance companies to transfer the longevity risks into the financial market. In this paper, with reference to Wang and Yue (2011) researches the design of longevity bonds to transfer longevity risk. Then setting up the trigger are very important to choice the kinds of mortality models. First, we adopt Lee-Carter model and Age-Period-Cohort model to fit and predict mortality rate regarded as triggers and premium. The purpose of this paper is to analyze different hedging strategies in terms of hedging costs. Hedging strategies include reinsurance, bond and mortality bonds. A and mortality-based securities, such as mortality bonds, a comparison of different triggers has been studied to find out which trigger will benefit investors or life insurance companies

Characteristics of Karst Cave Development in Urban Karst Area and Its Effect on the Stability of Subway Tunnel Construction

The existence of karst caves poses a large threat to safe tunnel construction in a karst area. This paper presents a synthetic method to evaluate the collapse risk before subway tunnel construction with Yang-Jian interval tunnel as a case study. The crosshole seismic Computed Tomography (CT) integrated with Geological Drilling (Geo-D) was first applied to accurately delineate the karst location and its scale. Then, 483 groups of seismic wave CT images were recorded, and 524 karst cave anomalies were found. The height of karst caves in the study area is 1–20 m and mainly concentrated at approximately 5 m. The vertical distance between the karst cave and the tunnel is mainly within 15 m. According to the detection results, a series of numerical models were built and calculated using FLAC3D to investigate the effect of different sizes and locations of karst caves on the displacement and stability of the surrounding rock in tunnels. Afterwards, based on the simulation results, the disturbance degree evaluation index was established to quantitatively evaluate the risk level of karst caves. The evaluation results indicate that the buried depth of the karst cave greatly affects the disturbance degree. No treatment is required for the deeply buried karst cave that is more than 7 m from the tunnel. When the distance between the cave and the tunnel is less than 7 m, there is a critical size of the cave. Karst caves that are larger than that critical value must be filled with a single slurry or binary slurry before tunnel construction to eliminate the risk of tunnel collapse. This study can be used to provide a more efficient and economical program for metro tunnel construction above a karst cave

Study on the Influence of Different Prophase Stress Levels on the Fatigue Damage Characteristics of Granite

In order to reveal the influence of prophase stress levels on the fatigue damage characteristics of granite, uniaxial fatigue tests of granite with different prophase stress levels were carried out on the basis of the MTS 815.04 rock mechanics test system. The results show that, under the same number of cycles, the failure degree increases with the increase of the prophase stress level. Under the low upper limit of cyclic stress, the tangent modulus and dissipated energy increase significantly with the increase of prophase stress level at the early stage of the cycle loading, while the increasing trend is not obvious with the increase of prophase stress level at the late stage. Under the high upper limit of cyclic stress, the tangent modulus and dissipated energy are less affected by the prophase stress level. The development trend of elastic release energy is not obvious with the increase of prophase stress level, which is less affected by the number of cycles. From the damage parameters defined by dissipative energy, under the low upper limit of cyclic stress, the initial damage is less affected by the prophase stress level. With the increase of the number of cycles, the influence of the prophase stress level on the development trend of the damage variable increases gradually. And the development trend of damage variables shows “C-shaped” damage

Metabolic response of soybean leaves induced by short-term exposure of ozone

The ever-increasing ozone (O-3) concentration has led to reduced production and altered quality of soybean. Abundant reports have explored the damage mechanisms of O-3 on soybean. However, how the elevated O-3 affects metabolite profiling of soybean remains to be poorly understood. Here, we compare the metabolic profile of soybean leaves under charcoal filtered air (CF, <20 ppb) and short-term elevated O-3 concentration (EO, 100 ppb). High level of O-3 affects metabolites for the tricarbonic acid (TCA) cycle, reactive oxygen species, cell wall composition and amino acids. Significantly, jasmonic acid-related metabolite promoting stomata closure is highly induced with 125-fold change. Furthermore, O-3 fumigation alters the expression of genes contributing to the biosynthesis of certain metabolites in TCA cycle. Together, these findings identify a wide range of changed metabolites in response to O-3 pollution. Our results pave the way for the genetic improvement of soybean to adapt to O-3 pollution to maintain stable yields