scholarly journals Storage targets optimization embedded with analytical hedging rule for reservoir water supply operation

2017 ◽  
Vol 18 (2) ◽  
pp. 622-629 ◽  
Author(s):  
Jing Wang ◽  
Tiesong Hu ◽  
Xiang Zeng ◽  
Muhammad Yasir
Keyword(s):  
Water Supply ◽  
Water Shortage ◽  
Water Release ◽  
Reservoir Water ◽  
Hedging Rule ◽  
New Model ◽  
Proposed Model ◽  
Maximum Water ◽  
Period Model

Abstract A two-period model is widely used to derive optimal hedging rules for reservoir water supply operation, often with storage targets as the goal to conserve water for future use. However, the predetermined storage targets adopted in the two-period model result in shortsighted decisions without considering the control of long-term reservoir operation. The purpose of this paper is to propose a new model to seek a more promising water supply operation policy by embedding the hedging rule derived from the two-period model in an optimization program for storage targets. Two modules are incorporated in the new model: the two-period model for optimizing water release decisions in each period with given storage targets and the optimization module to determine the optimal values of storage targets for connecting different periods. The Xujiahe water supply system is taken as a case study to verify the effectiveness of the proposed model. The results demonstrate that the new model is superior to others based on standard operation policy or rule curves during droughts and reduces the maximum water shortage.

scholarly journals A Model to Decompose Property Rental Multipiers with Regard to the Division Between Land and Building Elements

2016 ◽  
Vol 24 (1) ◽  
pp. 51-63
Author(s):  
S.A. Smolyak
Keyword(s):  
Cash Flow ◽  
Flow Analysis ◽  
Discounted Cash Flow ◽  
Building Element ◽  
New Model ◽  
Proposed Model ◽  
Long Term Forecasting ◽  
The Impact ◽  
Building Elements

Abstract We propose a new model for the decomposition of rental multipliers for the property building element which also supports valuation of income-producing real properties based on the principle of stability and an un-orthodox application of discounted cash flow analysis. Having regard to the building/land element analytical split of overall property, the proposed model explicitly accounts for the impact of the value of underlying land on the decomposition of rental multipliers, and doesn’t require long-term forecasting of income.

scholarly journals Derived Storage Allocation Rules to Meet Shared Water Demands for Optimal Operation of an Inter-basin Multi-reservoir Water Supply System

2021 ◽  
Author(s):  
Fang Wan ◽  
Yu Wang ◽  
Lingfeng Xiao ◽  
Qihui Chai
Keyword(s):  
Water Supply ◽  
Optimal Allocation ◽  
Water Shortage ◽  
Optimal Operation ◽  
Allocation Rule ◽  
Storage Allocation ◽  
Reservoir Water ◽  
Allocation Rules ◽  
Water Demands ◽  
Supply Capacity

The priority principle of storage allocation rules of serial cascade reservoirs within an inter-basin water supply can reduce water loss and reduce water supply times. Reasonable balancing curves for reservoirs in parallel are proposed and the proportional distribution of water is determined to illustrate the optimal allocation rule for different scheduling periods of reservoirs. The mutation point and slope are used to describe the segmentation of reservoirs in parallel. In addition, the optimization model is established with the objective function to minimize times of water shortage while the particle swarm optimization algorithm based on the immune evolutionary algorithm is applied to calibrate the balancing curves. Finally, the relative optimal water supply rule is obtained, providing a larger water supply capacity and higher storage synchronization of member reservoirs. The reservoir groups downstream of Luan River are used as an example, with the results showing that the suggested method can effectively improve the operational performance and meet shared water demands in an inter-basin multi-reservoir. This article highlights the superior results obtained compared to the current storage allocation rules to meet shared water demands.

A blockchain approach to digital archiving: digital signature certification chain preservation

2020 ◽  
Vol 30 (3) ◽  
pp. 345-362 ◽  
Author(s):  
Vladimir Bralić ◽  
Hrvoje Stančić ◽  
Mats Stengård
Keyword(s):  
Digital Signature ◽  
Information Disclosure ◽  
Digital Signatures ◽  
Digital Archiving ◽  
Content Type ◽  
New Model ◽  
Proposed Model ◽  
Certificate Chain ◽  
Long Term Preservation

Purpose The short lifespan of digital signatures presents a challenge to the long-term preservation of digitally signed records. It can undermine attempts to presume, verify or assess their authenticity. This paper aims to investigate the challenges of the expiration of digital signatures in the context of digital archiving. Design/methodology/approach The paper identifies requirements for the long-term preservation of digitally signed records and compares them with the existing approaches. The characteristics, operational procedures and requirements of the technologies used for digital signatures are combined with the archival requirements to design a new model. Findings The paper proposes a new model of a blockchain-based system, which can be combined with any digital archive to assist the process of long-term preservation of digitally signed records. Practical implications The proposed model offers a new alternative to the current practice in the long-term preservation of digitally signed records, such as periodic resigning procedures or periodic wrapping of digitally signed records with archival timestamps. Originality/value The proposed TrustChain 2.0 model is based on previous research conducted as part of the InterPARES Trust project. It builds on TrustChain 1.0 by including digital signature certificate chain validity information in a blockchain thus avoiding the issues concerning records confidentiality and privacy information disclosure. The paper contributes not only to the development of archival science but also shows archival institutions on how to approach long-term preservation of digitally signed records.

Dynamic operating rules for water supply reservoirs in La Paz

2002 ◽  
Vol 46 (6-7) ◽  
pp. 247-254 ◽  
Author(s):  
M.J. Bender ◽  
D. Hranisavljevic ◽  
R. Bernardin ◽  
R. Bianchi
Keyword(s):  
Water Supply ◽  
Water Shortage ◽  
Water Levels ◽  
Short Term ◽  
Flexible Tool ◽  
La Paz ◽  
Operating Rules ◽  
Dynamic Operating ◽  
Water Supply Reservoirs

Dynamic operating rules have been applied to the drought-prone Andean water supply reservoirs near La Paz, Bolivia. The water supply reservoirs are not using conventional reservoir operating rule curves. Instead, dynamic operating rules opportunistically supply surplus water for soft demands, and proactively adjust the water supply before a drought causes a water shortage. The conventional approach of forcing water levels to follow a set rule curve is replaced with notions of tradeoffs between long-term reliability and short-term supply opportunities. Operators can customise the dynamic rules based on their tolerance of shortages, and can choose to operate more aggressively during wet periods. In this way, the dynamic rules offer a flexible tool for making short-term decisions while managing medium and long-term performance goals. In the case of La Paz, it is possible to utilise the water sources more efficiently in the short-term without significantly reducing the long-term water supply reliability. The dynamic rules will reduce the severity of future water shortages (if they occur) by 60%, and provide opportunities to increase the firm water supply by up to 8% without affecting the long-term reliability.

scholarly journals MODELLING OF HUMAN EXPERT DECISION MAKING IN RESERVOIR OPERATION

2015 ◽  
Vol 77 (22) ◽  
Author(s):  
Wan Hussain Wan Ishak ◽  
Ku Ruhana Ku-Mahamud ◽  
Norita Md Norwawi
Keyword(s):  
Decision Making ◽  
Water Supply ◽  
Water Level ◽  
Sliding Window ◽  
Water Release ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Human Expert ◽  
Rainfall Season ◽  
Window Technique

Reservoir is one of the structural approaches for flood mitigation and water supply.  During heavy raining season, reservoir operator has to determine fast and accurate decision in order to maintain both reservoir and downstream river water level.  In contrast to less rainfall season, the reservoir needs to impound water for the water supply purposes. This study is aimed to model human expert decision making specifically on reservoir water release decision. Reservoir water release decision is crucial as reservoir serve multi purposes.  The reservoir water release decision pattern that comprises of upstream rainfall and current reservoir water level has been form using sliding window technique.  The computational intelligence method called artificial neural network was used to model the decision making.  

New Model of Bone Reconstruction Specially Designed for Skull Base Surgery—Long-Term Testing in Primates

Skull Base ◽  
2007 ◽  
Vol 17 (S 1) ◽  
Author(s):  
Cleopatra Charalampaki ◽  
Axel Heimann ◽  
Laszlo Kopacs ◽  
Oliver Kempski
Keyword(s):  
Skull Base ◽  
Skull Base Surgery ◽  
Bone Reconstruction ◽  
New Model

A new model for the induction of proestrus-like LH surges by estradiol in long-term ovariectomized rats

1985 ◽  
Vol 110 (1_Suppla) ◽  
pp. S11
Author(s):  
C. HIEMKE ◽  
A. SCHMID ◽  
R. GHRAF
Keyword(s):  
Ovariectomized Rats ◽  
New Model

Enhanced rapid gravity filtration and dissolved air flotation for pre-treatment of river thames reservoir water

1998 ◽  
Vol 37 (2) ◽  
pp. 35-42 ◽  
Author(s):  
M. J. Bauer ◽  
R. Bayley ◽  
M. J. Chipps ◽  
A. Eades ◽  
R. J. Scriven ◽  
...  
Keyword(s):  
Water Treatment ◽  
Water Supply ◽  
21St Century ◽  
Reservoir Water ◽  
Dissolved Air Flotation ◽  
Lowland Rivers ◽  
Air Flotation ◽  
Pre Treatment ◽  
Counter Current ◽  
Dissolved Air

Thames Water treats approximately 2800Ml/d of water originating mainly from the lowland rivers Thames and Lee for supply to over 7.3million customers, principally in the cities of London and Oxford. This paper reviews aspects of Thames Water's research, design and operating experiences of treating algal rich reservoir stored lowland water. Areas covered include experiences of optimising reservoir management, uprating and upgrading of rapid gravity filtration (RGF), standard co-current dissolved air flotation (DAF) and counter-current dissolved air flotation/filtration (COCO-DAFF®) to counter operational problems caused by seasonal blooms of filter blocking algae such as Melosira spp., Aphanizomenon spp. and Anabaena spp. A major programme of uprating and modernisation (inclusion of Advanced Water Treatment: GAC and ozone) of the major works is in progress which, together with the Thames Tunnel Ring Main, will meet London's water supply needs into the 21st Century.

Modeling of unforced demand response programs

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hassan Jalili ◽  
Pierluigi Siano
Keyword(s):  
Demand Response ◽  
Load Shifting ◽  
Response Models ◽  
Temperature Changes ◽  
Proposed Model ◽  
Equipment Failures ◽  
Demand Response Programs ◽  
Simultaneous Implementation ◽  
Long Term Studies

Abstract Demand response programs are useful options in reducing electricity price, congestion relief, load shifting, peak clipping, valley filling and resource adequacy from the system operator’s viewpoint. For this purpose, many models of these programs have been developed. However, the availability of these resources has not been properly modeled in demand response models making them not practical for long-term studies such as in the resource adequacy problem where considering the providers’ responding uncertainties is necessary for long-term studies. In this paper, a model considering providers’ unavailability for unforced demand response programs has been developed. Temperature changes, equipment failures, simultaneous implementation of demand side management resources, popular TV programs and family visits are the main reasons that may affect the availability of the demand response providers to fulfill their commitments. The effectiveness of the proposed model has been demonstrated by numerical simulation.

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