The THUDSOS Distributed Operating System

The THUDSOS is a distributed operating system modeled as an abstract machine which provides de- centralized control,transparency,availability,and reliability,as well as a good degree of autonomy at each node,that makes our distributed system usable.Our operating system supports transparent access to data through network wide filesystem.The simultaneous access to any device is discussed for the case when the peripherals are treated as files.This operating system allows spawning of parallel applica- tion programs to solve problems in the fields,such as numerical analysis and artificial intelligence.

Dawning-1000 PROOS Distributed Operating System

PROOS is a distributed operating system running on the computing nodes of massively parallel processing computer Dawning-1000. It is an efficient and easily extendible micro kernel operating system. It supports the intel NX message passing interface for communication.

Naming in the Distributed Operating System ZGL

In this paper,the naming scheme used in the heterogeneous distributed operating system ZGL is described and some of the representative techniques utilized in current distributed operating systems are examined.It is believed that the partitioning of the name space into many local name spaces and one global shared name space allows the ZGL system to satisfy each workstation's demand for local autono- my and still be able to facilitate transparent resource sharing.By the division of the system into clusters and the use of a combined centralized-distributed naming mechanism,the system is able to avoid both the bottleneck problem caused by a single centralized name server for the whole system and the per- formance degradation due to a full distributed scheme.

Transactive control:a framework for operating power systems characterized by high penetration of distributed energy resources

The increasing number of distributed energy resources connected to power systems raises operational challenges for the network operator, such as introducing grid congestion and voltage deviations in the distribution network level, as well as increasing balancing needs at the whole system level. Control and coordination of a large number of distributed energy assets requires innovative approaches. Transactive control has received much attention due to its decentralized decision-making and transparent characteristics. This paper introduces the concept and main features of transactive control, followed by a literature review and demonstration projects that apply to transactive control. Cases are then presented to illustrate the transactive control framework. At the end, discussions and research directions are presented, for applying transactive control to operating power systems, characterized by a high penetration of distributed energy resources.

A Mechanism Supporting the Client/Server Relationship in the Operating System of Distributed System “THUDS”

This paper presents a distributed operating system modeled as an abstract machine that provides all the distributed processes with the same set of services.The kernel of our operating system supports ser- vices which are achieved by a remote procedure call on requests by parallel processes.Therefore,a scheme for solving the client-server relationship is required.In our system there are more than one cli- ents and,at least,a receive would he required for each.Similarly,there are more than one servers such that the send in a client should produce a message that can he received by every server. Consequently,a mechanism well suited for programming multiple-clients/single-server and sin- gle client/multiple-servers interactions is proposed.

A Dynamic Load Balancing Mechanism for Distributed Systems

It is desirable in a distributed system to have the system load balanced evenly among the nodes so that the mean job response time is minimized. In this paper, we present.a dynamic load balancing mechanism (DLB). It adopts a centralized approach and is network topology independent. The DLB mechanism employs a set of thresholds which are automatically adjusted as the system load changes. lt also provides a simple mechanism for the system to switch between periodic and instantaneous load balancing policies with ease. The performance of the proposed algorithm is evaluated by intensive simulations for various parameters. The simulAtion results show that the mean job response time in a system implementing DLB algorithm is significantly lower than the same system without load balancings. Furthermore, compared with a previously proposed algorithm, DLB algorithm demonstrates improved performance, especially when the system is heavily loaded and the load is unevenly distributed.

Measurement-Device-Independent Quantum Key Distribution with Two-Way Local Operations and Classical Communications

Measurement-device-independent quantum key distribution （MDI-QKD） is proven to be immune to all the de- tector side channel attacks. With two symmetric quantum channels, the maximal transmission distance can be doubled when compared with the prepare-and-measure QKD. An interesting question is whether the transmission distance can be extended further. In this work, we consider the contributions of the two-way local operations and classical communications to the key generation rate and transmission distance of the MDI-QKD. Our numerical results show that the secure transmission distances are increased by about 12kin and 8 km when the 1 13 and the 2 B steps are implemented, respectively.

A Non-Forced-Write Atomic Commit Protocol for Cluster File Systems

Distributed metadata consistency is one of the critical issues of metadata clusters in distributed file systems. Existing methods to maintain metadata consistency generally need several log forced write operations. Since synchronous disk IO is very inefficient, the average response time of metadata operations is greatly increased. In this paper, an asynchronous atomic commit protocol （ACP） named Dual-Log （DL） is presented. It does not need any log forced write operations. Optimizing for distributed metadata operations involving only two metadata servers, DL mutually records the redo log in counterpart metadata servers by transferring through the low latency network. A crashed metadata server can redo the metadata operation with the redundant redo log. Since the latency of the network is much lower than the latency of disk IO, DL can improve the performance of distributed metadata service significantly. The prototype of DL is implemented based on local journal. The performance is tested by comparing with two widely used protocols, EP and S2PC-MP, and the results show that the average response time of distributed metadata operations is reduced by about 40%-60%, and the recovery time is only I second under 10 thousands uncompleted distributed metadata operations.

Stable single-mode operation of a distributed feedback quantum cascade laser integrated with a distributed Bragg reflector

We report an index-coupled distributed feedback quantum cascade laser by employing an equivalent phase shift(EPS) of quarter-wave integrated with a distributed Bragg reflector(DBR) at λ~5.03 μm. The EPS is fabricated through extending one sampling period by 50% in the center of a sampled Bragg grating. The key EPS and DBR pattern are fabricated by conventional holographic exposure combined with the optical photolithography technology, which leads to improved flexibility, repeatability, and cost-effectiveness. Stable single-mode emission can be obtained by changing the injection current or heat sink temperature even under the condition of large driving pulse width.

A Tabu-search-based Algorithm for Distribution Network Restoration to Improve Reliability and Resiliency

Fault restoration techniques have always been crucial for distribution system operators(DSOs).In the last decade,it started to gain more and more importance due to the introduction of output-based regulations where DSO performances are evaluated according to frequency and duration of energy supply interruptions.The paper presents a tabu-searchbased algorithm able to assist distribution network operational engineers in identifying solutions to restore the energy supply after permanent faults.According to the network property,two objective functions are considered to optimize either reliability or resiliency.The mathematical formulation includes the traditional feeders,number of switching operation limit,and radiality constraints.Thanks to the DSO of Milan,Unareti,the proposed algorithm has been tested on a real distribution network to investigate its effectiveness.

Grid Integration of Electric Vehicles for Economic Benefits:A Review

Emissions from the internal combustion engine(ICE) vehicles are one of the primary cause of air pollution and climate change. In recent years, electric vehicles(EVs) are becoming a more sensible alternative to these ICE vehicles. With the recent breakthroughs in battery technology and large-scale production, EVs are becoming cheaper. In the near future,mass deployment of EVs will put severe stress on the existing electrical power system(EPS). Optimal scheduling of EVs can reduce the stress on the existing network while accommodating large-scale integration of EVs. The integration of these EVs can provide several economic benefits to different players in the energy market. In this paper, recent works related to the integration of EV with EPS are classified based on their relevance to different players in the electricity market. This classification refers to four players: generation company(GENCO), distribution system operator(DSO), EV aggregator, and end user. Further classification is done based on scheduling or charging strategies used for the grid integration of EVs. This paper provides a comprehensive review of technical challenges in the grid integration of EVs along with their solution based on optimal scheduling and controlled charging strategies.

A Review on TSO-DSO Data Exchange,CIM Extensions and Interoperability Aspects

The exchange of information between transmission system operators(TSOs)and distribution system operators(DSOs)is a common practice.However,the evolution of the regulatory frameworks in Europe has increased the need for enhancing TSO-DSO data exchange and interoperability.This paper provides an overview of the TSO-DSO data exchanges and demonstrates the best practices using International Electrotechnical Commission(IEC)common information model(CIM),including the implementation of IEC common grid model exchange standard(CGMES),and discussion of the corresponding advantages,disadvantages,and challenges.Furthermore,this paper evaluates and reports the activities already carried out within European projects,with particular focus on TSO-DSO interoperability.Finally,this paper concludes the need for TSOs and DSOs to rely on standard-based solutions when performing TSO-DSO data exchange,which enables the efficient operation and development of the future power systems.

Prediction of voltage distribution using deep learning and identified key smart meter locations

The energy landscape for the Low-Voltage(LV)networks is undergoing rapid changes.These changes are driven by the increased penetration of distributed Low Carbon Technologies,both on the generation side(i.e.adoption of micro-renewables)and demand side(i.e.electric vehicle charging).The previously passive‘fit-and-forget’approach to LV network management is becoming increasing inefficient to ensure its effective operation.A more agile approach to operation and planning is needed,that includes pro-active prediction and mitigation of risks to local sub-networks(such as risk of voltage deviations out of legal limits).The mass rollout of smart meters(SMs)and advances in metering infrastructure holds the promise for smarter network management.However,many of the proposed methods require full observability,yet the expectation of being able to collect complete,error free data from every smart meter is unrealistic in operational reality.Furthermore,the smart meter(SM)roll-out has encountered significant issues,with the current voluntary nature of installation in the UK and in many other countries resulting in low-likelihood of full SM coverage for all LV networks.Even with a comprehensive SM roll-out privacy restrictions,constrain data availability from meters.To address these issues,this paper proposes the use of a Deep Learning Neural Network architecture to predict the voltage distribution with partial SM coverage on actual network operator LV circuits.The results show that SM measurements from key locations are sufficient for effective prediction of the voltage distribution,even without the use of the high granularity personal power demand data from individual customers.

Euler Operator and Homogeneous Hida Distributions

Let（S）L2（S’（IR）,μ）（S）* be the Gel’fand triple over the white noise space （S’（IR）,μ）.Let（en,n≥0）be the ONB of L2（IR）consisting of the eigenfunctions of the s.a. operator-（d/（dt））2+1+t2.In this paper the Euler operator △E is defined as the sum ∑i【,ei)i, where i stands for the differential operator Dei.It is shown that △E is the infinitesimal gen- erator of the semigroup（Tt）,where(Tt)（x）=（etx）for ∈（S）.Similarly to the finite dimensional case,the λ-order homogeneous test functionals are characterized by the Euler equa- tion:△E=λ.Via this characterization the λ-order homogeneous Hida distributions are defined and their properties are worked out.