Corridor Width Research Articles

Evaluation of the Thermal Environmental Effects of Urban Ecological Networks—A Case Study of Xuzhou City, China

Urban heat islands (UHIs) constitute an important ecological problem in cities. Ecological space has a positive effect on UHI mitigation, which can be effectively organized in the form of ecological networks. In this study, the framework for structural UHI improvement based on ecological networks considering the source-corridor model is proposed to examine the spatial threshold of the thermal effect of ecological network factors. Additionally, the cooling mechanism of each constituent element in the ecological network context is further explored. The results demonstrate that (1) an obvious cold and heat island spatial aggregation distribution exists in the Xuzhou main urban area, and land of the same land use type exhibits the dual thermal environmental properties of cold and heat islands through its spatial distribution and characteristics. Ecological space is the main bearing area of cold islands. (2) The ecological network in the main urban area of Xuzhou city occurs at a moderately complex level, and the overall network efficiency is acceptable; the network connectivity is low, while the network loop distribution is uneven. (3) Ecological networks represent an effective spatial means to improve overall UHI patterns. The ecological source area cooling threshold is 300 m, and the optimal threshold is 100 m, while the ecological corridor width threshold is 500 m and 60 m, respectively. (4) Within the optimal threshold in the context of ecological networks, the temperature of ecological sources in category G land is influenced by NDBI and FVC; ecological corridors are mainly influenced by NDBI. The results can provide a quantitative basis for urban ecological network planning considering UHI improvement and a reference for urban thermal environment research within different ecological substrates and planning and control systems in other countries and regions worldwide.

Integrating CVOR-GWLR-Circuit model into construction of ecological security pattern in Yunnan Province, China.

In the traditional construction of ecological security pattern, the minimum cost path is extracted as the ecological corridor based on the minimum cumulative resistance model, and the ecological nodes are identified manually. This method lacks the consideration of the exchange process of energy flow and information flow in the ecological process, resulting in a certain lack of ecological security pattern in structure and function. Therefore, an ecological security pattern construction method integrating CVOR-GWLR-Circuit model is proposed to solve the above problems by transforming natural background data into localized correction variables and adding them to the ecological security pattern evaluation model. Taking Yunnan Province as an example, firstly, the ecological security evaluation system of "Contribution, Vigor, Organization, Resilience" (CVOR) is constructed based on the importance of ecosystem services and ecosystem health, and the ecological security of Yunnan Province in 2020 is evaluated, and the ecological source areas are identified combined with nature reserves. Then, the ecological resistance surface was constructed by considering land use data and topographic factors, and the landslide sensitivity evaluation model was constructed based on geographically weighted logistic regression model (GWLR) to correct the basic resistance surface. Finally, the circuit theory model is used to extract the ecological corridor and construct the ecological security pattern in Yunnan Province. The ecological pinch points and barriers in the ecological corridor are diagnosed by the current density, so as to identify the width of the ecological corridor and identify the key areas of ecological protection and restoration. The results showed that the ecological sources area of Yunnan Province was about 69,417.78 km2, accounting for 17.6% of the total area of the study area, mainly distributed in Dehong Prefecture, southwest Yunnan, Diqing Prefecture and Nujiang Prefecture in northwest Yunnan. A total of 780 ecological corridors were generated between the ecological sources, with a total length of about 197,598.2km, an average length of 253.3km, and the longest path length of 932.1km. The ecological corridors are "spider web", linking southwest, northwest, northeast, central and southeast Yunnan Province. 36 ecological pinch points and 42 ecological barriers were identified. The research results verify that the ecological security pattern constructed by integrated CVOR-GWLR-Circuit model is more reasonable, which can provide scientific basis for regional ecological protection planning and ecological corridors design.

Research on calculated method for space electric field around HVDC transmission lines with buildings nearby

High voltage direct current (HVDC) transmission technology has incomparable advantages in long-distance and large-capacity transmission. With the development of HVDC transmission technology, transmission lines inevitably pass through some densely populated and economically developed areas. Due to environmental considerations, the space electric field around the buildings that are adjacent to HVDC transmission lines has aroused increasing attention. However, it is hard to be predicted by simulation because of the calculation complexity. This paper proposed a new calculated method to obtain the composite electric field around HVDC transmission lines with adjacent residential buildings, and the validity and correctness of the method are verified by the experimental results. Then, the distortion of the electric field around the building and its impact on the design of the safe corridor width of the HVDC transmission line is analyzed. The proposed method, unlike existing methods, can be used to predict the space composite electric field distribution around HVDC transmission lines and their adjacent residences, which are of arbitrary material, shape, and size. It can provide guide for the optimal design of transmission line corridors.

Using Reformatted Axial Computed Tomography Images in Isolation Will Miss Narrow S1 Transsacral Screw Corridors.

To evaluate S1 transsacral (TS) corridors on reformatted and nonreformatted computed tomography (CT) images to determine which most reliably identifies narrow corridors. Retrospective cohort. Level 1 trauma center. Two hundred forty-five patients with operative pelvic ring injuries. CT scan review. Preoperative CT scans were evaluated to determine the width of the S1 TS corridor on standard axial nonreformatted (ANR), axial reformatted (AR), and coronal reformatted images. Sensitivity and specificity of each format to detect a narrow corridor (<10 mm on AR or coronal reformatted) were calculated. Patients with S1 TS screws were evaluated to determine the rate of screw breach with narrow corridors. The axial width of the S1 TS corridor was consistently smaller on ANR versus AR images (mean difference 1.4mm, 95% confidence interval 1.1-1.5). The corridor width on ANR images was on average 86% of the AR measurement. ANR images had the highest sensitivity and specificity (100% and 98%) for detecting S1 TS corridors <10 mm. Fifty-three S1 TS screws were placed in corridors ranging 10-23 mm on AR images and 7-19 mm on ANR images. Four (57%) of the 7 screws placed in corridors less than 10 mm in width on ANR images breached the sacral cortex. Using ANR images to measure the S1 TS corridor consistently measured smaller widths than AR images and identified all narrow corridors. A high rate of screw breach was noted with screw placement in narrow corridors. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

An attempt to distinguish physical and socio-psychological influences on pedestrian bottleneck.

It has been realized that the distinction between social-psychological effects and physical effects in pedestrian crowds is complex, and so the relevance of social psychology for the properties of pedestrian streams is still discussed controversially. Although physics-based models appear to capture many properties rather accurately, it was argued that simple systems of self-driven particles could not explain certain emergent phenomena. In particular, results from a recent empirical study of pedestrian flow at bottlenecks have been interpreted as indicating the relevance of social psychology even in relatively simple scenarios of crowd dynamics. The study showed a surprising dependence of the density near the bottleneck on the width of the corridor leading to it. The density increased with increasing corridor width, although a wider corridor provides more space for pedestrians. It has been argued that this observation is a consequence of social norms, which trigger the effect by a preference for queuing in such situations. However, convincing evidence for this hypothesis is still missing. Here, we reconsider this scenario from a physics perspective using computer simulations of a simple microscopic velocity-based model.

Research of the International Experience of Arrangement of Proving Grounds Passable Terrain for Wheeled and Tracked Military Vehicles

The article presents the project data of construction designs for an estimation of passability of wheeled and tracked military vehicles for checking the parameters that are accepted as obligatory within the North Atlantic Treaty Organization (NATO). In particular, the constructions for determining the following parameters of passability are considered: ground clearance; angles of approach and departure; angle of climb; minimum turning radius; corridor width while turning with minimum radius; maximum angles of overcome gradients and side slope; maximum width of overcome vertical-sided ditch; maximum heights of overcome vertical wall and step; drawbar pull, speed and acceleration during mobility on the soft soil; and maximum depth of overcome water during fording.&#x0D; The project data is selected from the data of proving grounds for wheeled and tracked military vehicles and the relevant documents of the USA and the Russian Federation so that they don’t come in a contradiction with publications of the NATO.

The Influence of Harbin Forest–River Ecological Corridor Construction on the Restoration of Mollisols in Cold Regions of China

Artificial ecological corridors (AECs) are internationally approved ecological restoration and climate mitigation strategies. The width and recovery time indices of AECs directly affect the restoration efficiency of degraded soil nutrients. However, there is a lack of comprehensive and quantitative evaluation research on the construction factors of AECs from the perspective of soil fertility improvement. This research aimed to examine the critical ecological corridor construction factors affecting Mollisols’ eco-chemometrics and give a scientific scope. We collected 55 Mollisol samples at different restoration years (0–35 years) and different distances (0–280 m) from the AEC of the Ashi River, a typical Mollisol restoration area in Harbin, and the cold regions of China. We measured the distances, restoration years, soil thickness, pH, electrical conductivity (EC), cation exchange capacity (CEC), soil total organic carbon (SOC), soil total organic matter (SOM), dry matter content (DMC), and the proportion of nitrogen (TN), phosphorus (TP) and potassium (TK). The results are as follows: (1) Within the AEC, there were significant differences in soil stoichiometric characteristics in different restoration years and locations; after restoration for 10–35 years, the soil stoichiometric characteristics reach or exceed the reference value of Mollisols. (2) It is feasible to restore large-scale degraded Mollisols through ecological corridors. In this recovery process, the soil nutrients first decreased, then increased, and finally reached and exceeded the reference value of normal Mollisols. (3) Soil nutrient accumulation was related to ecological corridor width and recovery time. The recommended unilateral width of the ecological corridor based on Mollisols’ CEC and SOC indices for restoration is 175–225 m, and the restoration period is 22.7–35 years based on Mollisols’ EC and SOC indices for restoration. This study demonstrated the change mechanism of Mollisols in AECs based on recovery time and location, and provided the basis for the Chinese government to formulate policies for Mollisol remediation.

Endoscopic endonasal surgical anatomy through the prechiasmatic sulcus: the key window to suprachiasmatic and infrachiasmatic corridors

Classically, the transtuberculum and transplanum approaches have been utilized to reach the suprachiasmatic and infrachiasmatic corridors. The aim of this study was to provide a better understanding of the key endoscopic endonasal anatomy of the suprachiasmatic and infrachiasmatic corridors provided through selective removal of the prechiasmatic sulcus (SRPS). A SRPS was performed in 16 sides of 8 alcohol-fixed head specimens. Twenty anatomical measurements were collected on the suprachiasmatic and infrachiasmatic corridors. The transplanum and transtuberculum approaches were also performed. In the suprachiasmatic corridor, the SRPS exposed the anterior communicating artery (AComm) and the post-communicating segment of the anterior cerebral arteries in all the cases, while the pre-communicating segment of the anterior cerebral arteries, recurrent arteries of Heubner, and fronto-orbital arteries were visualized in 75% (12/16), 31% (5/16), and 69% (11/16) of cases, respectively. In the infrachiasmatic corridor, the ophthalmic segment of the internal carotid artery and superior hypophyseal arteries were always visible through the SRPS. The mean width and height of the prechiasmatic sulcus were 13.2mm and 9.6mm, respectively. The mean distances from the midpoint of the AComm to the anterior margin of the optic chiasm (OCh) was 5.3mm. The mean width of the infrachiasmatic corridor was 12.3mm at the level of the proximal margin of the ophthalmic segment of the internal carotid artery. The mean distances from the posterior superior limit of the pituitary stalk to the basilar tip and oculomotor nerve were 9.7mm and 12.3mm, respectively. The SRPS provides access to the main neurovascular and cisternal surgical landmarks of the suprachiasmatic and infrachiasmatic corridors. This anatomical area constitutes the key part of the approach to the suprasellar area. To afford adequate surgical maneuverability, the transplanum or transtuberculum approaches are usually a necessary extension.

Forklift with small turning radius and its efficiency

Abstract A forklift is one of the most widely used vehicles in industry sectors in few decades. Therefore, it is important to create or improve their entire designs. This article proposes a method for determining the required corridor width by calculating the turning radius of standard counterweight Forklift and the new construction of forklift and compares their parameters. The effect of the new type of fork on the efficiency of forklifts and warehouses was studied.

An integrated approach to constructing ecological security patterns and identifying ecological restoration and protection areas: A case study of Jingmen, China

ContextAs urbanization continues, ecosystem stability faces serious challenges. Ecological security patterns have become a main tool with which the contradictions between economic development and ecological security can be alleviated and even solved. ObjectiveIn this study, ecological patches were identified based on ecosystem services, and ecological corridors were derived using a minimum cumulative resistance model. We analyzed the importance and connectivity of ecological corridors using a gravity model and the probability of connectivity index and identified key restoration and protection areas. ResultsThe results show that (1) 72 ecological patches were identified in Jingmen, and important patches were distributed in the western mountainous areas of Jingmen. (2) The corridor connectivity in Jingmen needs to be improved. The 71 ecological corridors with the lowest cumulative resistance were identified; these corridors were mainly concentrated in mountainous areas, forest parks, and wetland parks. ConclusionWe suggested 100–200 m as the ecological corridor width in Jingmen, as this width could balance the economic development, ecological conservation, and food security priorities. We identified 15 priority protection areas and 11 priority restoration areas that urgently require reasonable ecological restoration in Jingmen. This construction of an ecological security pattern in Jingmen provides a scientific reference for urban ecological planning and urban spatial layout planning and achieves a win–win situation in which both smart urban growth and ecological protection can be realized.

An optimisation approach for designing wildlife corridors with ecological and spatial considerations

Abstract The fragmentation of wildlife habitats caused by anthropogenic activities has reduced biodiversity and impaired key ecosystem functions. Wildlife corridors play an important role in linking detached habitats. The optimal design of such corridors considering spatial, ecological and economic factors is addressed in this paper. We present a novel graph‐theoretic optimisation approach and a mixed‐integer linear programming model to determine an optimal wildlife corridor connecting two given habitat patches. The model maximises the total quality of the corridor and satisfies pre‐specified corridor width and length requirements under a resource constraint. Compared to the corridor design models presented in the literature, our model is conceptually simpler, and it is computationally convenient. We applied the model to a real dataset for Eldorado National Forest in California, USA, involving 1,363 irregular land parcels. The model can be extended to design multiple corridors that connect two or more existing habitat patches.

Iliac dysmorphism: defining radiographic characteristics and association with pelvic osseous corridor size.

Insertion of iliac wing implants requires understanding of the curvilinear shape of the ilium. This study serves to quantitatively identify the area of iliac inner-outer table convergence (IOTC), characterize the iliac wing osseous corridor, and define the gluteal pillar osseous corridor. Computed tomography scans of 100 male and 100 female hemipelves were evaluated. The iliac wing was studied using manual best-fit analysis of the bounds of the inner and outer cortices. The IOTC was defined as the location of the iliac wing with an intercortical width less than 5mm. The shortest distance from the apex of the iliac crest to the superior border of the IOTC was defined as the iliac wing osseous corridor. Finally, the width of the gluteal pillar corridor from the gluteus medius tubercle to the ischial tuberosity was measured. The IOTC is an elliptical area measuring 22.3 cm2. All ilia had an area where the inner and outer cortices converged to an intercortical width of less than 5mm; 48% converged to a single cortex. The shortest mean distance from the superior edge of the iliac crest to the beginning of the IOTC was 20.3mm in men and 13.8mm in women (p < 0.001). The gluteal pillar diameter averaged 5.3mm in men and 4.3mm in women (p < 0.001). All ilia converge to a thin and frequently unicortical central region. A 4.5mm iliac wing lag screw will not breach the cortex if it remains within 20mm or 14mm distal to the cranial aspect of the iliac crest in males and females, respectively. Not only is the gluteal pillar smaller than previously thought, in 41% of males and 73% of females, it is not be large enough for 5mm implants. This study quantitatively assesses the dimensions of the IOTC, the iliac crest osseous corridor, and the gluteal pillar. Overall, our findings provide improved understanding of the limits for implant use in the iliac wing as well as better appreciation of the complex osteology of the ilium. This will help surgeons to identify safe areas for implant placement and avoid inadvertent cortical penetration.

Numerical Study of Bottleneck Flow with Varying Corridor Width and Motivation Using a Speed-Based Model

In this study a simple speed-based model is employed to simulate an experiment of pedestrian bottleneck flow. The experiment revealed that the density near the bottleneck is influenced by the motivation of the pedestrians and the corridor width. In narrow corridors, distinct lanes are formed for pedestrians with low motivation. These lanes can disappear when the pedestrians have a high motivation to reach their target. We show that a speed-based model is - despite its relative simplicity- capable to reproduce the observed phenomena to a high degree.

Computed Tomographic Evaluation of Mid-thoracic Vertebral Corridors in Normal French Bulldogs

Objectives: (1) To report internal measurements of thoracic vertebral bone morphology and (2) identify safe and clinically applicable surgical implant corridors in the T7-T9 thoracic vertebrae of French Bulldogs. &#x0D; Study Design: Observational, cross‐sectional, descriptive study.&#x0D; Sample Population: Seven client-owned French Bulldogs with normal thoracic vertebrae.&#x0D; Methods: Computed tomographic (CT) studies of normal French Bulldogs were reviewed. Multiplanar reconstruction of the CT images was used to determine thoracic vertebral corridors. Corridor measurements included the width, length, insertion distance off midline, and angle off midline (sagittal) for each thoracic vertebra. One‐way analysis of variance was used to detect differences between groups.&#x0D; Results: Measurements of vertebral corridor width (p&gt;0.9848), length (p&gt;0.8113), implant center (p&gt;0.9282) and angle (p&gt;0.3609) did not differ between each vertebra. The average vertebral corridor width was 4.5 ± 0.7 mm. The average corridor length was 17.2 ± 2.5 mm. The average corridor angle was 22.3 ± 1.9 °. The mean distance the proposed implant center was from the vertebral midline was 8.2 ± 1.1 mm. Inter-observer agreement of corridor length and implant center was good but poor for corridor angle and width.&#x0D; Conclusion: Based on average corridor width and length, commercially available cortical screws or pins can be utilized for implants in this region of the thoracic spine. The angle of corridor trajectory from a dorsal approach seems most applicable for T7-T9.&#x0D; Clinical Significance: Vertebral corridors can be measured using CT-MPR, and implant specifications and angles derived. Surgical guides can also be created to guide implant placement. This approach provides a simple and accurate method to guide the placement of thoracic vertebral implants.

Parking Planning Under Limited Parking Corridor Space

Automatic parking systems are increasingly used in daily life, and the restriction of parking spaces will make parking more difficult. This paper proposes parallel parking and forwards vertical parking path planning algorithms considering the park-ing corridor space. First, an anthropomorphic parallel parking path planning using parking space is proposed for the limited space over the length of the parking corridor. Second, a for-ward vertical parking path planning algorithm is proposed con-sidering the width of the parking space corridor. Third, the tar-get line set for parallel parking and vertical parking paths is generated. At the same time, the target line set considers the error factor and then selects the target line. Fourth, the clothoid solves the problem of discontinuous curvature of the parking path. Finally, a driver model is constructed to follow the gener-ated parking path, and the parking planning method proposed in this paper is compared with other methods.

Entry Guidance Command Generation for Hypersonic Glide Vehicles Under Threats and Multiple Constraints

A novel entry guidance command generation (EGCG) method for hypersonic glide vehicles (HGVs) is proposed in this paper. Apart from the conventional path constraints, terminal constraints, and multiple stationary geographic constraints, the method takes into account several threats that HGVs must avoid during the entry process. The threats are classified into covert threats and dynamic threats. The information of covert threats needs to be detected during the entry process, and the positions of dynamic threats are even unfixed. A piecewise analytical polynomial height-velocity profile is used to derive an analytical magnitude expression for bank angle commands. The profile is capable of taking full advantage of the width of the entry corridor and satisfying large range requirements in flight missions. An improved artificial potential field (IAPF) is introduced to formulate the lateral guidance law, which allows the HGV to pass all the waypoints, circumvent no-fly zones, and maneuver to avoid threats. Finally, several simulations are conducted to demonstrate the effectiveness of the designed method. The proposed EGCG method exhibits a superior ability to satisfy multiple constraints and avoid threats, accuracy to target point arrival, and strong robustness against uncertainties and deviations.

Beringia and the Settlement of the Western Hemisphere

Previously, we addressed the problem of what variable(s) limited widespread human settlement of the Americas before ~15 ka. We concluded that while non-modern human taxa (e. g., Neanderthals) probably did not inhabit high-latitude environments (due to cold climate and/ or low plant and animal productivity) and thus could not disperse in the Western Hemispherevia Beringia, modern humans likely were denied access to mid-latitude North America &gt;15 ka by coastal and interior ice sheets. Here we reexamine the problem with respect to modern humans in light of a revised chronology for glaciers and sea level, new research in paleo-genomics, and some new archaeological discoveries. During 35–30 ka, a lineage with west Eurasian roots occupied the Great Arctic Plain and may have expanded into eastern arctic Beringia and mid-latitude North America via an ice-free corridor. An East Asian lineage associated with microblade technology occupied the Lena Basin during the LGM and expanded onto the Great Arctic Plain &gt;15 ka, possibly as early as the GI 2 interstadial (24–23 ka). Their immediate descendants probably occupied the southern Bering Land Bridge and Northwest Pacific coast &gt;15 ka and dispersed widely in the Western Hemisphere during GI 1 (14.5–12.9 ka), primarily if not exclusively via a coastal route. The coalesced Laurentide and Cordilleran ice sheets blocked interior access to mid-latitude America until 13.8 ± 0.5 ka (and possibly later due to the length and narrow width of the ice-free corridor &gt;13 ka).

河流生态廊道提取方法研究及其应用思路

PDF HTML阅读 XML下载 导出引用 引用提醒 河流生态廊道提取方法研究及其应用思路 DOI: 10.5846/stxb202102090415 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家水体污染控制与治理科技重大专项（2018ZX07110003）；国家自然科学基金（31670467） Research progress on methods of river ecological corridor extraction and their application Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:随着交叉学科的发展和技术手段的进步，将河流及其周边生态环境视为整体的理念和研究逐渐受到重视，然而国内对河流生态廊道的研究较少。总结了河流生态廊道的基础理论和提取方法。河流生态廊道可以依据区域规划、通过实地观测等手段直接提取，也可以采用"源地识别-阻力面构建-廊道提取"的框架间接提取。对直接和间接提取方法进行了详细的总结并分析了他们的优势和劣势，发现间接提取方法更具实践意义，且应用的流域面积更大。根据间接提取方式的特点，提出白洋淀-大清河流域河流生态廊道提取的思路。结合区域流域协同治理理念，逐步形成以白洋淀为中心、向周边辐射的河流生态廊道，实现流域水质提升、生物多样性稳定等目标，全面提升生态环境质量。在河流生态廊道提取科学性提升和提取过程中廊道宽度优化等薄弱环节提出未来研究方向。 Abstract:The over exploitation of natural sources leads to a huge burden on water, air, and other environment, among which the response of water environment is the most direct and rapid. With the interdisciplinary development and technology progress, more and more attention has been paid to rivers and their surrounding ecological environment as an integrated river ecological corridor, but there are few researches on river ecological corridor in China. This article summarizes the fundamental theory and extraction methods of river ecological corridor. The river ecological corridor can be defined as the river itself, the riparian vegetation zone along the river and all the related ecological elements, through which river network and ecological flow connect. The extraction methods of river ecological corridor can be classified to direct or indirect categories. The river ecological corridor can be directly extracted according to regional planning or field observation, or indirectly by the framework of "source identification-resistance surface construction-corridor extraction". The patches with high ecosystem service value are often identified as the source area; the resistance surface is often constructed by different environmental variables, such as land use type, elevation, slope, and others, and these environmental variables are given weight according to experience or expert consultation; then the ecological corridor is extracted by different models combining source area and resistance surface. In this paper, these two extraction methods are summarized in detail, and their advantages and disadvantages are discussed as well. The results show that the indirect extraction method has more practical significance, and can more clearly explain the connectivity between patches in a larger watershed. Meanwhile, the indirect extraction method is more time-saving and convenient with the help of RS and GIS technology. With the advantages of indirect extraction method, the extraction idea of river ecological corridor in Baiyangdian-Daqing River Basin is proposed. The area of Baiyangdian-Daqing River Basin is 45000 km2, including Xiong'an New Area and Tianjin Binhai Industrial belt. Different industrial clusters drive the development of whole basin. Incorporated with the ideas of region and watershed collaborative management, a river ecological corridor radiating outwards from the core-Baiyangdian Wetland is gradually formed, thereby realizing the goal of water quality improvement and biodiversity stability in the river basin, and comprehensively improving the quality of reginal ecological environment. At the end, future research directions are proposed in the weak links of scientific improvement of river ecological corridor extraction and width optimization of river ecological corridor. 参考文献 相似文献 引证文献

Transmission of Omicron (B.1.1.529) - SARS-CoV-2 Variant of Concern in a designated quarantine hotel for travelers: a challenge of elimination strategy of COVID-19

Transmission of Omicron (B.1.1.529) - SARS-CoV-2 Variant of Concern in a designated quarantine hotel for travelers: a challenge of elimination strategy of COVID-19

Maximizing with‐profit pensions without guarantees

AbstractPension providers are currently running into trouble mainly due to the ultra‐low interest rates and the guarantees associated to some pension benefits. In this paper, we aim to reduce the pension volatility and provide adequate pension levels—with no guarantees—through a new pension design. Under this design, the individual's premium is split into an individual and a collective account, both invested in funds. When the return from the individual fund exceeds a predefined corridor, a certain number of units is transferred to or from the collective account. In this way, the volatility of the individual fund is smoothed. By controlling the corridor width, we maximize the total accumulated capital at retirement.