Placement Cost Research Articles

Dynamic and intelligent edge server placement based on deep reinforcement learning in mobile edge computing

In the era of 5G and beyond, Mobile Edge Computing (MEC) has emerged as a technology that seamlessly integrates wireless networks and the Internet, enabling low-latency and high-reliability computing services for mobile users. A crucial prerequisite for deploying MEC is the strategic selection of edge server locations that can satisfy computing demands and improve resource utilization. In this paper, we study the problem of efficient and intelligent dynamic edge server placement considering time-varying network states and placement costs. We present a long-term dynamic decision-making process that models edge server placement as a Markovian decision process and dynamically adjusts server layout. To achieve intelligent decision-making, we propose two deep reinforcement learning-based algorithms. Namely, the DBPA algorithm based on D3QN and the PBPA algorithm based on PPO, which significantly improve the efficiency and performance of model training. We also propose a novel method for transforming network states into network inputs using heat map and grayscale map to enhance the agent’s learning efficiency. Experimental results demonstrate that our proposed algorithms achieve intelligent and dynamic placement of edge servers, and outperform comparison algorithms by 13.20% to 61.84% and 23.09% to 66.32%, respectively.

119 An Institutional Analysis of Venous Sinus Stenting and Cerebrospinal Fluid Shunting for Idiopathic Intracranial Hypertension

INTRODUCTION: Idiopathic intracranial hypertension (IIH) is a debilitating disease that can present with severe vision loss. Although medical management is the first-line treatment, these cases commonly require intervention by either ventriculoperitoneal/pleural shunting (VPS) or, more recently, by venous sinus stenting (VSS). Unfortunately, this chronic disease can lead to multiple clinical encounters which increases financial burden. Therefore, identifying ways to effectively treat IIH definitively while limiting healthcare costs are of great interest. METHODS: This is a retrospective study of IIH patients diagnosed via modified Dandy criteria who received VPS (n=27) or VSS (n=27) from May 2008–May 2019. Visual outcomes were reported by a neuro-ophthalmologist at approximately 1-month post-procedure. Costs of emergency department as well as and outpatient/inpatient encounters for neurosurgery and ophthalmology were obtained from the index procedure to 3 years post-procedure. RESULTS: VSS patients had higher pre-intervention ophthalmology evaluation rates (stents: n = 22, 88.9%; shunts: n = 7, 23.1%; p < 0.0001). Papilledema was present in most patients (VSS 82.6% vs VPS 66.7%, p = 0.60) and all patients had stable/improved papilledema at follow-up. Two VSS patients (4.9%) required a second stent. Four VSS patients (9.8%) had a VPS placed. No VPS patients received a VSS. Encounter cost for VSS placement were more expensive than primary VPS placement ($10,749 vs $13,648; p = 0.002). However, at 1.5 years after index procedure, cumulative VPS cost surpassed VSS and persisted at 3 years ($22,674 vs $17,441, p = 0.039). CONCLUSIONS: VPS and VSS have similar visual outcomes with all cases having stable or improved papilledema. The upfront cost of VSS is greater than VPS; however, VPS quickly surpasses VSS in cost by 1.5 years after index procedure and continues to study endpoint at 3 years. These results may help guide multi-disciplinary care for patients with IIH.

Comparison of temporal-to-frontal horn shunt and ventriculo-peritoneal shunt for treatment of trapped temporal horn: a retrospective cohort study.

As a localized hydrocephalus, trapped temporal horn (TTH) can be effectively resolved via cerebrospinal fluid shunting. In addition to conventional ventriculo-peritoneal shunt (VPS), temporal-to-frontal horn shunt (TFHS) has been described as a less complex and invasive procedure with promising results; however, there is limited data comparing VPS to TFHS regarding patient outcomes. This study aims to compare TFHS versus VPS for treatment of TTH. We conducted a comparative cohort study with patients undergoing TFHS or VPS for TTH after surgery of trigonal or peritrigonal tumors between 2012 and 2021. The primary outcome was revision rates at 30-day, 6-month, and 1-year. Secondary outcomes included operative duration, postoperative pain, hospital stay, overdrainage, and cost for shunt placement and revision. A total of 24 patients included, with 13 (54.2%) patients receiving TFHS and 11 (45.8%) receiving VPS. Both cohorts shared similar baseline characteristics. There were no significant differences between TFHS and VPS in 30-day (7.7% vs 9.1%, p > 0.99), 6-month (7.7% vs 18.2%, p = 0.576), or 1-year (8.3% vs 18.2%, p = 0.590) revision rates. There were no significant differences in terms of operative duration (93.5 ± 24.1 vs 90.5 ± 29.6min, p = 0.744), surgical site pain (0 vs 18.2%, p = 0.199), or postoperative length of stay (4.8 ± 2.6 vs 6.9 ± 4.0days, p = 0.157) between the two groups. For the TFHS cohort, no patient experienced shunt related overdrainage, and there was a trend towards fewer overdrainage (0% vs 27.3%, p = 0.082) compared with VPS. TFHS offered significant reduction in cost for initial shunt (¥20,417 vs ¥33,314, p = 0.030) and total costs for shunt and revision (¥21,602 vs ¥43,196, p = 0.006) compared to VPS. As a technique of valveless shunt and without abdominal incision, TFHS is cosmetic, cost-effective, and completely free of overdrainage with similar revision rates as compared with VPS.

Orthodontic treatment with miniscrew anchorage: Analysis of quality of information on YouTube

The evaluation of the quality of information (QOI) and clarity of information (COI) among oral health-related videos on the video-streaming Web site YouTube is scarce. This study evaluated QOI and COI regarding temporary anchorage devices contained within videos uploaded by dental professionals (DPs) on YouTube. YouTube videos were systematically acquired with 4 search terms. The top 50 videos per search term by the number of views were stored in a YouTube account. A set of inclusion/exclusion criteria were applied, videos were assessed for viewing characteristics, a 4-point scoring system (0-3) was applied to evaluate QOI in 10 predetermined domains, and a 3-point scoring system (0-2) was applied to evaluate COI. Descriptive statistical analyses and intrarater and interrater reliability tests were performed. Strong intrarater and interrater reliability scores were observed. Sixty-three videos from the top 58 most-viewed DPs were viewed 1,395,471 times (range, 414-124,939). Most DPs originated from the United States (20%), and orthodontists (62%) uploaded most of the videos. The mean number of reported domains was 2.03 ± 2.40 (out of 10). The mean overall QOI score per domain was 0.36 ± 0.79 (out of 3). The "Placement of miniscrews" domain scored highest (1.23 ± 0.75). The "Cost of miniscrews placement" domain scored the lowest (0.03 ± 0.25). The mean overall QOI score per DP was 3.59 ± 5.64 (out of 30). The COI in 32 videos was immeasurable, and only 2 avoided using technical words. The QOI related to temporary anchorage devices contained within videos provided by DPs through the YouTube Web site is deficient, particularly in the cost of placement. Orthodontists should be aware of the importance of YouTube as an information resource and ensure that videos related to temporary anchorage devices contain comprehensive and evidence-based information.

Energy-optimal DNN model placement in UAV-enabled edge computing networks

Unmanned aerial vehicle (UAV)-enabled edge computing is emerging as a potential enabler for Artificial Intelligence of Things (AIoT) in the forthcoming sixth-generation (6G) communication networks. With the use of flexible UAVs, massive sensing data is gathered and processed promptly without considering geographical locations. Deep neural networks (DNNs) are becoming a driving force to extract valuable information from sensing data. However, the lightweight servers installed on UAVs are not able to meet the extremely high requirements of inference tasks due to the limited battery capacities of UAVs. In this work, we investigate a DNN model placement problem for AIoT applications, where the trained DNN models are selected and placed on UAVs to execute inference tasks locally. It is impractical to obtain future DNN model request profiles and system operation states in UAV-enabled edge computing. The Lyapunov optimization technique is leveraged for the proposed DNN model placement problem. Based on the observed system overview, an advanced online placement (AOP) algorithm is developed to solve the transformed problem in each time slot, which can reduce DNN model transmission delay and disk I/O energy cost simultaneously while keeping the input data queues stable. Finally, extensive simulations are provided to depict the effectiveness of the AOP algorithm. The numerical results demonstrate that the AOP algorithm can reduce 18.14% of the model placement cost and 29.89% of the input data queue backlog on average by comparing it with benchmark algorithms.

Bus Voltage Violations under Different Solar Radiation Profiles and Load Changes with Optimally Placed and Sized PV Systems

This study mainly discusses the implications of solar radiation profiles and changes in load with respect to base load conditions on the PV placement, size, voltage violations, and curtailment cost of PV generation in the network. The PV installation is optimized using yearly solar radiation profiles, low, medium, and high, corresponding to three different locations. The network in the study is represented as a multiphase, with provision for the installation of both single- and three-phase PV systems. For the different load changes in either one of the phases or all three phases, the optimal placement and size of PV inverters are discussed. It is indicated that with load increase in all three phases, for low solar radiation profiles, the placement and size of PVs remain non-uniform, while for medium and high solar radiation, the distribution becomes comparatively uniform throughout the network. However, with a load increase in one of the phases, for low solar radiation, optimal placement compensates with three-phase PV installation, while for medium/high solar, the corresponding load increase phase contributes to greater PV installation. The voltage rise is observed at both load-connected and non-load-connected buses. Such buses in the network are those that form the common junction with the branches connected to another set of buses having optimally placed PVs. The voltage violations are experienced at the feeder end buses with single-phase PV installation, not only in the phase having a connected load but also in one of the other phases.

Cost-Efficient Virtual Network Function Placement in an Industrial Edge System: A Proposed Method

Edge computing has been a promising framework to provide effective computing services for edge users in most industrial environments. Due to the limited resources at the edge, it is not suitable for massive requirements such as the virtual reality process, communication, and so on. Cloud computing can provide sufficient resources for those requirements, but it has some latency lags. Industrial edge clouds enable flexible service providers for industrial applications by merging edge and cloud computing. The virtual network function (VNF) is one approach, while placement is a dominant solution. However, this solution may increase the cost of communication as the nodes are more distant. In this article, we investigate the resource allocation problem for VNF placement in industrial edge systems. The aim is to minimize the overall cost of the whole placement procedure, including operating cost, communication cost, and placement cost. We formulate this VNF placement problem as an integer programming problem, and due to the complexity of the problem, we propose a heuristic method to solve it. Numerical simulation shows that our proposed method can significantly cut down the cost while meeting the multiple resource constraints.

Effectiveness and Cost of Stenting in Ureteral Injury in Colorectal Surgeries in the US: 2015 - 2019.

Intraoperative ureteral injury (IUI) during colorectal surgery can have devastating consequences. This study aimed to assess the clinical and economic impact of pre-operative ureteral stenting in colorectal surgeries. A retrospective cohort study was conducted using United States hospital data (October 2015 - December 2019). IUI incidence was examined across selected inpatient surgery types (elective colectomy, enterectomy, proctectomy, enterostomy, other colorectal procedures; emergency colectomy). Stenting effectiveness was evaluated as the difference in IUI and intraoperative detection rates between propensity score-matched groups. The additional hospital cost for stenting was also estimated considering the savings from IUIs that were potentially avoidable or detected by stenting. In total, 283,549 colorectal surgeries were analyzed. Across surgery types, stent use and IUI incidence ranged from 1.47% - 8.86% and from 0.91% - 2.90%, respectively. Stents were used in 6.75% of elective colectomy cases, where they were associated with an absolute reduction of 1.14 percentage points (95% CI: -1.85 to -1.03) in IUI rate and a 21.6 percentage point reduction in the intraoperative detection rate. Additional hospital costs for stenting ranged from $1,464 - $4,436 across surgery types. Additional results varied by case but were consistent with the colectomy example. While effective in limited settings, the IUI reduction attributed to stenting and ability to shift IUI detection to the intraoperative setting could not offset the hospital cost of stent placement during colectomy (and colorectal surgery, in general). There thus remains an ongoing need in colorectal surgery for a universal, cost-effective solution to prevent IUI.

SFC Design and VNF Placement Based on Traffic Volume Scaling and VNF Dependency in 5G Networks

The development of Fifth-Generation (5G) mobile communication technology has remarkably promoted the spread of the Internet of Things (IoT) applications. As a promising paradigm for IoT, edge computing can process the amount of data generated by mobile intelligent devices in less time response. Network Function Virtualization (NFV) that decouples network functions from dedicated hardware is an important architecture to implement edge computing, deploying heterogeneous Virtual Network Functions (VNF) (such as computer vision, natural language processing, intelligent control, etc.) on the edge service nodes. With the NFV MANO (Management and Orchestration) framework, a Service Function Chain (SFC) that contains a set of ordered VNFs can be constructed and placed in the network to offer a customized network service. However, the procedure of NFV orchestration faces a technical challenge in minimizing the network cost of VNF placement due to the complexity of the changing effect of traffic volume and the dependency on the VNF relationship. To this end, we jointly optimize SFC design and VNF placement to minimize resource cost while taking account of VNF dependency and traffic volume scaling. First, the problem is formulated as an Integer Linear Programming (ILP) model and proved NP-hard by reduction from Hamiltonian Cycle problem. Then we proposed an efficient heuristic algorithm called Traffic Aware and Interdependent VNF Placement (TAIVP) to solve the problem. Compared with the benchmark algorithms, emulation results show that our algorithm can reduce network cost by 10.2% and increase service request acceptance rate by 7.6% on average.

Application of visual placement of a nasojejunal indwelling feeding tube in intensive care unit patients receiving mechanical ventilation.

Compared with nasogastric nutrition, nasojejunal nutrition may prevent some complications of critically ill patients by maintaining better nutritional status, and blind placement of nasojejunal dwelling feeding tubes is widely used. However, the visual placement seems to be safer and more effective than the blind placement, and is still seldom reported. We tried to develop visual placement of a nasojejunal feeding tube in intensive care unit patients. A total of 122 patients receiving mechanical ventilation were admitted to the Department of Critical Care Medicine of the Fifth Affiliated Hospital of Wenzhou Medical University and received the placement of nasojejunal feeding tubes. These patients were randomly and evenly assigned into two groups, one group receiving visual placement of nasojejunal dwelling feeding tubes and another group receiving blind placement. Actual tube placement was confirmed by X-ray. The primary outcome included the success rates of first placement of feeding tubes. The secondary outcome included the time of tube placement, complications, the total cost, heart rates and respiratory rates. The primary outcome showed that the success rates of first placement were 96.70% (59 cases/61 cases) in the visual placement group, and two cases failed due to pyloric stenosis and gastroparesis. The success rates were 83.6% (51 cases/61 cases) in the blind placement group and 10 cases failed due to either wrong placement or retrograde tube migration. The success rates in the visual placement group were higher than that in the blind placement group (P = 0.015). The secondary outcome showed that the time of tube placement in the visual placement group was shorter than that in the blind placement group (P < 0.0001). The cost of tube placement in the visual placement group was higher than that in the blind placement group (P < 0.0001). The statistical differences in complications, heart and respiratory rates were insignificant between the two groups (P > 0.05). Compared with the blind placement, the visual placement shortened the time of nasojejunal tube placement and increased success rates of first placement. The visual placement was more efficient, easy to operate, safe, and has potential clinical applications.

DDEL-02. LUMBAR OMMAYA RESERVOIR- A COST EFFECTIVE ALTERNATIVE TO INTRAVENTRICULAR OMMAYA RESERVOIR FOR TREATMENT OF LEPTOMENINGEAL DISEASE

Abstract Introduction Lumbar puncture (LP) is a well-established approach for intrathecal (IT) delivery of chemotherapeutics for leptomeningeal disease (LMD). Intraventricular Ommaya reservoir (OR) has supplanted LPs as an easier and safer route for IT administration. Radiotherapy for treatment of LMD must be delayed in order for surgical wound healing following OR placement. Furthermore, prior cranial radiation can thin the scalp, predisposing to wound breakdown. Placement of lumbar Ommaya reservoir (LOR) provides an alternative to IT delivery, but this has not reached a wide-spread acceptance. Objective Provide cost-analysis and report patient outcomes after placement of LOR. METHODS Following IRB approval, all patients undergoing LOR placement between 2018 and 2020 were retrospectively reviewed. Patients age, primary tumor, survival lengths and complications were reviewed. Average procedure-related treatment cost was obtained from an uncomplicated representative case excluding the surgeon’s fee. RESULTS Fourteen patients (mean age 46.35 years) were identified. The mean follow-up was 440.7 (25-1003) days post-surgery. Acute lymphoblastic leukemia (n = 4), acute myeloblastic leukemia (n = 3), breast carcinoma (n = 3), ependymoma (n = 3), lymphoma (n = 2) and lung adenocarcinoma (n = 1) were identified as underlying malignancy. LMD was diagnosed on average after 581.1 days after the diagnosis of the underlying malignancy. 8 patients succumbed to their malignancy on average after 463.9 and 314.6 days after the diagnosis of LMD and LOR surgery, respectively. There were 2 complications – pain at the site of the LOR and a fractured catheter caused by inadvertent puncture of the catheter. No infections or wound healing complications were noted. Typical cost for placement of LOR and OR was – 17,350 USD and 29,052 USD, respectively. Placement of the LOR proved to be more cost-effective in this cohort by approximately 40% cost reduction. CONCLUSION Placement of LOR is a cost effective alternative to cranial OR with low complication profile, and well tolerated by patients.

Drops on surface optimization (DSO): A new reinforcement learning based metaheuristic algorithm for virtual network functions placement in distributed cloud architectures

With the goal of making the networks more agile, flexible and cost efficient, network function virtualization (NFV) is one of the latest and most promising technologies introduced. This technology is the key block of future internet and plays a critical role in modern networks. Using this paradigm, different network functions can be independently deployed on general purpose hardware instead of residing on dedicated hardware (network appliances in traditional networks). NFV enables faster development and lower costs. As any other new technology, NFV has some emerging challenges along with its benefits. The main research challenge of NFV is the necessity of optimally placing the virtual network functions (VNFs) in an NFV-enabled network. This problem is mainly known as the VNF placement (VNFP) problem in the literature. Due to the nature of network applications, this placement should be scalable for large network sizes. In this paper, the VNFP problem is addressed and a new metaheuristic algorithm is proposed based on the behavior of droplets on a surface, named the Drops on Surface Optimization (DSO) Algorithm. In order to enhance the proposed algorithm by dynamic selection strategy, a reinforcement learning approach (Q learning) is adopted. A comprehensive evaluation is carried out using standard networks, compared with several methods. Simulation results reveal that our proposed algorithm outperforms other state-of-the-art approaches in terms of total end-to-end propagation delay of the placed service chain, cost of placement, number of active servers involved in the placement and scalability.

Estabilidad de microtornillos en ortodoncia

Introducción: Las mini placas y los microtornillos se consideran dispositivos importantes en la ortodoncia actual. En efecto, este tipo de implantes alveolares fabricados de una aleación de titanio, representan los únicos auxiliares ortodónticos que proporcionan un anclaje absoluto. Sin embargo, los microtornillos se utilizan con mayor frecuencia por su costo accesible y facilidad de colocación y retiro. Objetivo: Analizar los factores que intervienen en la estabilidad de microtornillos ortodónticos. Metodología: Se efectuó un estudio transversal analítico y observacional, mediante el que se realizó una revisión bibliográfica de artículos publicados que abordan la temática de la estabilidad de microtornillos, en los tratamientos ortodónticos. Se analizó, comparó y se observaron sus ventajas, inconvenientes y posibles complicaciones. Conclusiones: Los factores que intervienen en la estabilidad de los microtornillos dependen de la experiencia del operador, características del paciente y las propiedades del microtornillo. Por lo tanto, es importante considerar estas variables para obtener mejores resultados en la clínica.

Cost Burden and Cost Influencers of Inferior Vena Cava Filter Placement and Retrieval among Medicare Beneficiaries with Acute Venous Thromboembolism

PurposeTo examine the frequency, costs, and cost influencers of inferior vena cava filters (IVCFs) placements and retrievals among a national sample of patients using Medicare data. Materials and MethodsThis retrospective cohort study used the U.S. Medicare 100% database, a nationally representative sample of all U.S. patients aged ≥65 years, from 2014 through 2020. Procedures and clinical characteristics were identified from the diagnosis and procedure codes on Medicare claims. Beneficiaries aged ≥65 years with newly diagnosed venous thromboembolism (VTE) were identified and followed to obtain data on IVCF placements and retrievals. Data on the costs of the index IVCF procedures and any subsequent IVCF placements and retrievals were obtained. Multivariate models were used to estimate the impact of patient and clinical characteristics on costs. ResultsAmong 501,216 patients with newly diagnosed VTE, 4,995 (1%) received an IVCF placement; of these, 1,215 (24.3%) had a retrieval procedure. Beneficiaries with IVCF placements and retrievals differed from a demographic and clinical perspective than from those without. Costs varied by the site of service, VTE acuity, and VTE type. Cost influencers included age, race, census region, service location, and VTE type. ConclusionsIVCF placement costs were driven by baseline patient characteristics (age, race, geographic residence, acute VTE diagnosis, and inpatient site of service), whereas retrieval costs were driven by age and deep vein thrombosis diagnosis. Strategies to mitigate the retrieval costs or the need to retrieve IVCFs may reduce the overall cost burden of IVCFs.

The effect of vertical load placement on metabolic rate during loaded walking in humans

We examined the effects of vertical load placement on the metabolic cost of walking. Twelve healthy participants walked on a treadmill with 13.8 and 23.4 kg loads in both high and low vertical positions. Metabolic rate was measured using respirometry. While load position had no effect on the net metabolic rate for the 13.8 kg load, the net metabolic rate with the 23.4 kg load was significantly reduced by 4.3% in the high vertical load position compared to the low vertical load position. Loads carried higher on the trunk were also associated with increased forward trunk lean that reduced the load gravitational moment arm in the sagittal plane suggesting that reduction of fore-aft upper body torques is an energy-saving mechanism during loaded walking. Practitioner Summary: Load placement within a backpack affects the biomechanics of load carriage. We experimentally tested the metabolic cost of high and low load placement during walking and found the high position to be less costly with large loads. Loading high may be the optimal technique for carrying heavy backpacks.

Combining Navigation and Manipulation Costs for Time-Efficient Robot Placement in Mobile Manipulation Tasks

Mobile manipulation tasks require a seamless integration of navigation and manipulation capabilities. Finding suitable robot placements to pick up and place objects in such tasks is crucial for time-efficient task execution. Sub-optimal robot placements result in infeasible solutions or require larger re-positioning of the mobile base to reach target objects, increasing the overall time to complete the task. In this work, we propose an approach that, given a set of objects, autonomously selects the optimal placements of a humanoid robot in conjunction with the best grasp candidate and corresponding arm. In contrast to previous approaches, our method considers both the navigation costs between consecutive robot placements and the manipulation costs to reduce the time needed to complete the task. We evaluate our method on a simulated table clearing task that requires the robot to move between pickup and discard locations and demonstrate the applicability in a real-world experiment on the humanoid robot ARMAR-6. In addition, we perform a run-time analysis and show that our approach can integrate sensory feedback to update the optimal placement in dynamic environments.

Optimization Methods for Feasible Deployment Planning of Future Mobile Networks

The exponential growth of mobile traffic requires mobile operators to update their network infrastructure to provide greater capacity and better connections for end-users. A promising alternative is to deploy heterogeneous networks (HetNets) that combine macrocells and small cells; however, this alternative increases the complexity and cost of transport (connections between the small cells and the operator’s control center). Most planning strategies outlined in the literature are aimed at reducing the number of small cells without considering important aspects involving transport (access backbone). With the advent of centralized architectures, this point becomes essential, since it is necessary to consider the potential impact of the transport segment on the deployment cost of the network (with the advent of the fronthaul). In this sense, this work proposes an optimal multiobjective model of radio and transport allocation based on linear programming to minimize the total cost of the network and two efficient heuristics to obtain a near-optimal solution. Considering a real case study of the literature, we show the cost (financial and computational) of the optimal placement of radio and transport infrastructure and the limitations of the solution. We also compare the proposed function placement heuristic with the optimal solution in terms of cost efficiency and execution time and demonstrate that it can provide a good estimation of the deployment cost in a much shorter time, with an approximation of up to 10% in relation to the optimal model.

Do Māori and Pacific Peoples Living with Dementia in New Zealand Receive Equitable Long-Term Care Compared with New Zealand Europeans?

<strong>Context:</strong> Compared to Europeans, Māori and Pacific peoples living with dementia in the Counties Manukau District Health Board region are three times less likely to use Aged Residential Care (ARC). <strong>Objectives: </strong>The aim of this study was to investigate whether reduced ARC utilisation by Māori and Pacific peoples living with dementia is equitably compensated by an increase in Home Based Support Service (HBSS). <strong>Methods:</strong> Routinely collected sociodemographic and clinical data for people diagnosed with dementia at an NZ memory service (2013–2019) were linked with administrative ARC and HBSS invoicing data. Two-part models were used to estimate adjusted costs of HBSS utilisation or ARC placement. <strong>Findings: </strong>six hundred fifty-seven people of European, Māori and Pacific ethnicity were included in the analysis. Compared to Europeans, both unadjusted and adjusted ARC costs per person-year were significantly lower for both Māori (–NZD$3580, 95%CI: –$6890, –$140) and Pacific peoples (–NZD$3110, 95%CI: –$5590, –$540) but HBSS cost per person-year was only higher for Pacific peoples (+NZD$640, 95%CI: $100, $1180) and not Māori (+NZD$180, 95%CI: –$470, $840). There was no significant difference in the combined HBSS and ARC cost per person-year for Māori (–NZD3460, 95%CI –7200, 280) or Pacific peoples (–NZD2490 95%CI –5090, 110). <strong>Conclusions:</strong> Lower ARC utilisation amongst Māori and Pacific peoples living with dementia does not translate to an equitable increase in HBSS spend. The difference is likely to be compensated by care provided by unpaid family carers. Addressing the wider determinants of long-term care use in these populations and providing alternative culturally appropriate services must be prioritised to address this inequity in allocation of public sector resources.

A Bifactor Approximation Algorithm for Cloudlet Placement in Edge Computing

Emerging applications with low-latency requirements such as real-time analytics, immersive media applications, and intelligent virtual assistants have rendered Edge Computing as a critical computing infrastructure. Existing studies have explored the cloudlet placement problem in a homogeneous scenario with different goals such as latency minimization, load balancing, energy efficiency, and placement cost minimization. However, placing cloudlets in a highly heterogeneous deployment scenario considering the next-generation 5G networks and IoT applications is still an open challenge. The novel requirements of these applications indicate that there is still a gap in ensuring low-latency service guarantees when deploying cloudlets. Furthermore, deploying cloudlets in a cost-effective manner and ensuring full coverage for all users in edge computing are other critical conflicting issues. In this article, we address these issues by designing a bifactor approximation algorithm to solve the heterogeneous cloudlet placement problem to guarantee a bounded latency and placement cost, while fully mapping user applications to appropriate cloudlets. We first formulate the problem as a multi-objective integer programming model and show that it is a computationally NP-hard problem. We then propose a bifactor approximation algorithm, ACP, to tackle its intractability. We investigate the effectiveness of ACP by performing extensive theoretical analysis and experiments on multiple deployment scenarios based on New York City OpenData. We prove that ACP provides a (2,4)-approximation ratio for the latency and the placement cost. The experimental results show that ACP obtains near-optimal results in a polynomial running time making it suitable for both short-term and long-term cloudlet placement in heterogeneous deployment scenarios.

Cost-effective management measures for coastal aquifers affected by saltwater intrusion and climate change.

Sustainable management of natural water resources and food security in the face of changing climate conditions is critical to the livelihood of coastal communities. Increasing inundation and saltwater intrusion (SWI) will likely adversely affect agricultural production and the associated beach access for tourism. This study uses an integrated surface-ground water model to introduce a new approach for retardation of SWI that consists of placing aquifer fill materials along the existing shoreline using Coastal Land Reclamation (CLR). The modeling results suggest that the artificial aquifer materials could be designed to decrease SWI by increasing the infiltration area of coastal precipitation, collecting runoffs from the catchment area, and applying treated wastewater or desalinated brackish water-using coastal wave energy to reduce water treatment costs. The SEAWAT model was applied to verify that it correctly addressed Henry's problem and then applied to the Biscayne aquifer, Florida, USA. In this study, to better inform Coastal Aquifer Management (CAM), we developed four modeling scenarios, namely, Physical Surface Barriers (PSB), including the artificial aquifer widths, permeability, and side slopes and recharge. In the base case scenario without artificial aquifer placement, results show that seawater levels would increase aquifer salinity and displace large amounts of presently available fresh groundwater. More specifically, for the Biscayne aquifer, approximately 0.50% of available fresh groundwater will be lost (that is, 41,192 m3) per km of the width of the aquifer considering the increasing seawater level. Furthermore, the results suggest that placing the PSB aquifer with a smaller permeability of <100 m per day at a width of approximately 615 m increases the available fresh groundwater by approximately 45.20 and 43.90% per km of shoreline, respectively. Similarly, decreasing the slope on the aquifer-ocean side and increasing the aquifer recharge will increase freshwater availability by about 43.90 and 44.50% per km of the aquifer. Finally, placing an aquifer fill along the shallow shoreline increases net revenues to the coastal community through increased agricultural production and possibly tourism that offset fill placement and water treatment costs. This study is useful for integrated management of coastal zones by delaying aquifer salinity, protecting fresh groundwater bodies, increasing agricultural lands, supporting surface water supplies by harvesting rainfall and flash flooding, and desalinating saline water using wave energy. Also, the feasibility of freshwater storage and costs for CAM is achieved in this study.