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CSE CSE 2102 2102 Software and Enterprise Architectures Prof. Steven A. Demurjian, Sr. Computer Science & Engineering Department The University of Connecticut 371 Fairfield Road, Box U-255 Storrs, CT 06269-2155 [email protected] http://www.engr.uconn.edu/~steve (860) 486 - 4818 Copyright © 2008 by S. Demurjian, Storrs, CT. 1 Software Architectures CSE 2102 Emerging Discipline in Mid-1990s Software as Collection of Interacting Components What are Local Interactions (within Component)? What are Global Interactions (between Components)? Advantages of SW Architectural Design Understand Communication/Synchronization Definition of Database Requirements Identification of Performance/Scaling Issues Detailing of Security Needs and Constraints Towards Large-Scale Software Development For Biomedical Informatics: What are Architectures for Data Sharing? How is Interoperability Facilitated? 2 Concepts of Software Architectures CSE 2102 Exceed Traditional Algorithm/Data Structure Perspective Emphasize Componentwise Organization and System Functionality Focus on Global and Local Interactions Identify Communication/Synchronization Requirements Define Database Needs and Dependencies Consider Performance/Scaling Issues Understand Potential Evolution Dimensions 3 The HTSS Software Architecture CSE CSE 2102 2102 IL IL IL SDO EDO SDO EDO Payment CR CR CR IL: CR: IC: DO: CR Item IC Order IC Item Locator Cash Register Inventory Invent. Control Control Deli Orderer for Shopper/Employee ItemDB Global Server ItemDB Local Server Non-Local Client Int. CreditCardDB ATM-BanKDB OrderDB SupplierDB 4 Multiple Backend Database System (MBDS) CSE CSE 2102 2102 Backend Database Processor Database Controller Backend Database Processor Host/User Backend Database Processor 5 The MBDS Processes CSE 2102 Database Controller Request Preparation Post Processing Put Msg. Get Msg. Get Msg. Put Msg. Directory Management Record Processing Concurrency Control Disk I/O Backend Database Processor 6 Multiple Processes in MBDS CSE 2102 No. 1 2 3 4 6 12 15 16 21 22 23 Type New Request Results of Request Number of Reqs in Transaction Aggregate Operators (Sum, etc.) Parsed Request to Backends Backend Aggregate Operator Results Ids for Accessing Database Indexes Request and Disk Addresses Ids for Accessing Database Records Locks Obtained: Okay to Execute Request ID of Finished Request SRC Host PoPr ReqP ReqP ReqP RecP DM DM DM CC RecP DST ReqP Host PoPr PoPr DM PoPr DMs RecP CC RecP CC 7 Message Passing in MBDS CSE 2102 A1 F15 From Other Backend Request Preparation D6 Put Msg. B3 C4 K12 Post Processing K12 Get Msg. E15 To Backend(s) Get Msg. Put Msg. D6,F15 E15 Directory Management G21 K12 H22 Record Processing I16 Concurrency Control J23 Disk I/O 8 Software Design Levels CSE 2102 Architecturally: Modules Interconnections Among Modules Decomposition into Subsystems Code: Algorithms/Data Structures Tasking/Control Threads Executable: Memory Management Runtime Environment Is this a Realistic/Accurate View? Yes for a Single “Application” What about Application of Applications? System of Systems? 9 Software Engineering - an Oxymoron? CSE 2102 Is there any Engineering? Is there any Science? Collection of Disparate Techniques: Data-Flow Diagrams E-R Diagrams Finite State Machines Petri Nets UML Class, Object, Sequence, Etc. Design Patterns Model Drive Architectures What is being “Engineered”? How do we Know we are Done? E.g. Does Artifact Match Specification? 10 What's Available for Engineering Software? CSE 2102 Specification (Abstract Models, Algebraic Semantics) Software Structure (Bundling Representation with Algorithms) Languages Issues (Models, Scope, User-Defined Types) Information Hiding (Protect Integrity of Information) Integrity Constraints (Invariants of Data Structures) Is this up to date? What else can be Added to List? Design Patters Model Driven Architectures XML –Data Modeling and Dependencies Others? 11 Engineering Success in Computing CSE 2102 Compilers Have Had Great Success Originally by Hand Then Compiler Compilers Parser Generators - Lex/Yacc Solid Science Behind Compilers Regular, Context Free, Context Sensitive Languages FSAs, PDAs, CFGs, etc. Science has Provided Engineering Success re. Ease and Accuracy of Modern Compiler Writing 12 History of Programming CSE 2102 C - Still Remains Industry Stronghorse Separate Compilation Decomposition of System into Subsystems, etc. Shared Declarations ADTs in C, But Compiler won't Enforce Them Modula-II and Ada 83 Had Information Hiding Public/Private Paradigm Module/Package Concepts Import/Export Paradigm Rigor Enforced by Compiler – but Can’t Bind/Group Modules into Subsystems Precisely Specify Interconnections and Interactions Among Subsystems and Components 13 ‘Recent-Past’ Generation? CSE 2102 C++ and Ada95 Considered “Legacy” Languages - Old Java, C# - Are they Headed Toward Legacy? How do they Rate? What Do they Offer that Hasn't been Offered Before? What are Unique Benefits and Potential of Java? What about new Web Technologies? Javascript, Perl, PhP, Phython, Ruby XML and SOAP How do all of these fit into this process? Particularly in Regards to C/S Solutions! 14 What's Next Step? CSE 2102 Architectural Description Languages Provide Tools to Describe Architectures Definition and Communication Codification of Architectural Expertise Frameworks for Specific Domains DB vs. GUI vs. Embedded vs. C/S Formal Underpinning for Engineering Rigor What has Appeared for Each of these? Struts for GUI Open Source Frameworks (mediawiki) Wide-Ranging Standards (XML) Model-Driven Architectures What Else??? 15 Architectural Styles CSE 2102 What are Popular Architectural Styles? How are they Characterized? Example in Practice Explore a Taxonomy of Styles Focus on “Micro-Architectures” Components Flow Among Components Represents “Single” Application Forms Basis for “Macro-Architectures” System of Systems Application of Applications Significantly Scaling Up 16 Taxonomy of Architectural Styles CSE 2102 Data Flow Systems Batch Sequential Pipes and Filters Call & Return Systems Main/Subroutines (C, Pascal) Object Oriented Implicit Invocation Hierarchical Systems Virtual Machines Interpreters Rule Based Systems Data Centered Systems DBS Hypertext Blackboards Independent Components Communicating Processes/Event Systems Client/Server Two-Tier Multi-Tier 17 Taxonomy of Architectural Styles CSE 2102 Establish Framework of … Components Building Blocks for Constructing Systems A Major Unit of Functionality Examples Include: Client, Server, Filter, Layer, DB Connectors Defining the Ways that Components Interact What are the Protocols that Mandate the Allowable Interactions Among Components? How are Protocols Enforced at Run/Design Time? Examples Include: Procedure Call, Event Broadcast, DB Protocol, Pipe 18 Overall Framework CSE 2102 What Is the Design Vocabulary? Connectors and Components What Are Allowable Structural Patterns? Constraints on Combining Components & Connectors What Is the Underlying Conceptual Model? Von Newman, Parallel, Agent, Message-Passing… Are their New Emerging Models? Collaborative Environments/Shareware? What Are Essential Invariants of a Style? Limits on Allowable Components & Connectors Common Examples of Usage Advantages and Disadvantages of a Style Common Specializations of a Style 19 Pipes and Filters CSE 2102 Components are Independent Entities. No Shared State! Components with Input and Output Sort Sort Merge Connectors for Flow Streams of I/O Filters: Invariant: Unaware of up and Down Stream Behavior Streamed Behavior: Output Could Go From One Filter to the Next One Allowing Multiple Filters to Run in Parallel. 20 Pipes and Filters CSE 2102 Possible Specializations: Pipelines - Linear Sequence Bounded - Limits on Data Amounts Typed Pipes - Known Data Format What is a Classic Example? Other Examples: Compilers Sequential Processes Parallel Processes 21 Pipes and Filters - Another Example CSE 2102 Text Information Retrieval Systems Scanning Newspapers for Key Words, Etc. Also, Boolean Search Expressions Where is Such an Architecture Utilized Today? What is Potential Usage in BMI? Search Controller User Commands Disk Controller Control Programming Result Query Resolver Term Comparator Search Data DB 22 ADTs and OO Architectures CSE 2102 Widespread Usage in the 1990’s Advantages Are Well Known op Components obj op Connectors op obj obj op op op obj op obj op op op obj op op op obj obj Disadvantages: Interaction Required Object Identity If Identity Changes, It Is Difficult to Track All Affected Objects. 23 Implicit Invocation CSE 2102 Similar to OO in the Sense that Components Can Call Services on Other Components How Does this Work? Components Have List of Events they can Raise and List of Procedures to Handle Events When Event is Raised, it is Broadcast All Components that Have Procedure to Handle Broadcast Event will Act Upon it The Component That Raised the Event has no Knowledge of Which Component(s) will Handle Event What are Some Examples? 24 Implicit Invocation CSE 2102 Advantages No Need to Know the Targeted Components Single Event can Impact Multiple Components New Event Handlers can Easily be Added New Events Can then be Raised Disadvantages No Control Over the Order of Processing When an Event is Raised No Control Over “Who” and “How Many” Process Events Very Non-Deterministic System Behavior 25 What has OO Evolved Into? CSE 2102 What has Classic OO Solution Evolved into Today? Client (Browser + Struts) Server (Many Variants of OO Languages) Database Server (typically Relational) Different Style (e.g., Design Pattern) Does Pattern Capture All Aspects of Style? Do we Need to Couple Technology with Pattern? Dr. D, Jan 01, 08 Fever, Flu, Bed Rest No Scripts No Tests Item(Phy_Name*, Date*, Visit_Flag, Symptom, Diagnosis, Treatment, Presc_Flag, Pre_No, Pharm_Name, Medication, Test_Flag, Test_Code, Spec_No, Status, Tech) 26 Layered Systems CSE 2102 Useful Systems Base Utility Core level Users Components - Virtual Machine at Each Layer Connectors - Protocols That Specify How Layers Interact Interaction Is Restricted to Adjacent Layers 27 Layered Systems CSE 2102 Advantages: Increasing Levels of Abstraction Support Enhancement - New Layers Support for Reuse Drawbacks: Not Feasible for All Systems Performance Issues With Multiple Layers Defining Abstractions Is Difficult. 28 Layered Systems in BMI CSE 2102 One Approach to Constructing Access to Patient Data for Clinical Research and Clinical Practice Construct Layered Data Repositories as Below Each Layer Targets Different User Group Need to Fine Tune Access Even within Layers Aggregated De-identified Patient Data Provider Cl. Researchers Public Health Researchers 29 ISO as Layered Architecture CSE 2102 ISO Open Systems Interconnect (OSI) Model Now Widely Used as a Reference Architecture 7-layer Model Provides Framework for Specific Protocols (Such as IP, TCP, FTP, RPC, UDP, RSVP, …) Application Presentation Session Transport Network Data Link Physical Application Presentation Session Transport Network Data Link Physical 30 ISO OSI Model CSE CSE 2102 2102 Application Presentation Session Transport Network Data Link Physical Application Presentation Session Transport Network Data Link Physical Physical (Hardware)/Data Link Layer Networks: Ethernet, Token Ring, ATM Network Layer Net: The Internet Transport Layer Net: Tcp-based Network Presentation/Session Layer Net: Http/html, RPC, PVM, MPI Applications, E.g., WWW, Window System, Algorithm 31 Repositories CSE 2102 ks8 ks1 Blackboard (shared data) ks2 ks3 ks6 ks4 ks7 ks5 Knowledge Sources Interact With the Blackboard. Blackboard Contains the Problem Solving State Data. Control Is Driven by the State of the Blackboard. DB Systems Are a Form of Repository With a Layer Between the BB and the KSs - Supports Concurrent Access, Security, Integrity, Recovery 32 Database System as a Repository CSE 2102 c8 c1 Database (shared data) c2 c3 c6 c4 c7 c5 Clients Interact With the DBMS Database Contains the Problem Solving State Data Control is Driven by the State of the Database Concurrent Access, Security, Integrity, Recovery Single Layer System: Clients have Direct Access Control of Access to Information must be Carefully Defined within DB Security/Integrity 33 Team Project as a Repository CSE 2102 c8 c1 Web Portal Shared c2 c3 c6 c4 c7 c5 Clients are Providers, Patients, Clinical Researchers Database Underlies Web Portal Simply a Portion of Architecture Interactions with PHR (Patients) Interactions with EMR (Providers) Interactions with Database/Warehouse (Researchers) 34 Interpreters CSE 2102 Inputs Outputs Program being interpreted Data (program state) Simulated interpretation engine Selected instruction Selected data Internal interpreter state What Are Components and Connectors? Where Have Interpreters Been Used in CS&E? LISP, ML, Java, Other Languages, OS Command Line 35 Java as Interpreter CSE CSE 2102 2102 36 Process Control Paradigms CSE 2102 Input variables Set point Ds to manipulated variables Controller Input variables Set point Controller Ds to manipulated variables With Feedback Process Controlled variable Without Feedback Process Controlled variable Also: Open vs. Close Loop Systems Well Defined Control and Computational Characters Heavily Used in Engineering Fields. 37 Process Architecture: Statechart Diagram? CSE CSE 2102 2102 38 Process Architecture: Activity Diagram? CSE CSE 2102 2102 Clear Applicability to Medical Processes that have Underlying BMI – Low Level Processes Waiting for Heart Signal timeout irregular beat Heartbeat Heart Signal Waiting for Resp. Signal Breath Trigger Local Alarm Trigger Remote Alarm Resp Signal Alarm Reset 39 Design Patterns as Software Architectures CSE 2102 Emerged as the Recognition that in Object-Oriented Systems Repetitions in Design Occurred Gained Prominence in 1995 with Publication of “Design Patterns: Elements of Reusable ObjectOriented Software”, Addison-Wesley “… descriptions of communicating objects and classes that are customized to solve a general design problem in a particular context…” Akin to Complicated Generic Usage of Patterns Requires Consistent Format and Abstraction Common Vocabulary and Descriptions Simple to Complex Patterns – Wide Range 40 The Observer Pattern CSE 2102 Utilized to Define a One-to-Many Relationship Between Objects When Object Changes State – all Dependents are Notified and Automatically Updated Loosely Coupled Objects When one Object (Subject – an Active Object) Changes State than Multiple Objects (Observers – Passive Objects) Notified Observer Object Implements Interface to Specify the Way that Changes are to Occur Two Interfaces and Two Concrete Classes 41 The Observer Pattern CSE CSE 2102 2102 42 Model View Controller CSE 2102 http://java.sun.com/blueprints/patterns/MVC-detailed.html 43 Model View Controller CSE 2102 Three Parts of the Pattern: Model Enterprise Data and Business Rules for Accessing and Updating Data View Renders the Contents (or Portion) of Model Deals with Presentation of Stored Data Pull or Push Model Possible Controller Translates Interactions with View into Actions on Model Actions could be Button Clicks (GUI), Get/Post http (Web), etc. 44 Model View Controller CSE 2102 http://java.sun.com/blueprints/patterns/MVC-detailed.html 45 UML for System Modeling CSE 2102 UML is a Language for Specifying, Visualizing, Constructing, and Documenting Software Artifacts What Does a Modeling Language Provide? Model Elements: Concepts and Semantics Notation: Visual Rendering of Model Elements Guidelines: Hints and Suggestions for Using Elements in Notation References and Resources Web: http://www.uml.org/ Is UML Sufficient for Complexity of BMI? Able to Model Information Needs for BMI? Able to Represent Required Architectures? 46 UML CSE 2102 UML is a Set of Graphical Specification Languages (OMG’s Standard Design Language Since November, 1997) Implementation Diagrams Component Diagrams: Show the Physical Structure of the Code in Terms of Code Components and Their Dependencies Deployment Diagrams: Show the Physical Architecture of the Hardware and Software in the System. They Have a Type and an Instance Version. 47 UML CSE 2102 When to Use Deployment Diagrams “… In practice, I haven’t seen this kind of diagram used much. Most people do draw diagrams to show this kind of information but they are informal cartoons. On the whole, I don’t have a problem with that since each system has its own physical characteristics that your want to emphasize. As we wrestle more and more with distributed systems, however, I’m sure we will require more formality as we understand better which issues need to be highlighted in deployment diagrams.” From “UML Distilled. Applying the Standard Object Modeling Language”, by Martin Fowler. Addison-Wesley, Object Technology Series, 7th. Reprint June, 1998. 48 Pros and Cons of Graphical Modeling CSE CSE 2102 2102 Advantages: Clear to Show Structure Excellent Communication Vehicle Addresses Different Aspects of Modeling in an Integrated Fashion Disadvantages: Shows Little (or No) Details There is a Big Gap Between Specification and Implementation Limited by Screen Size & Printable Page Solution: Associate a Complete Textual Specification to Graphical Model that Contains the Necessary Details for Each Element 49 Design Concepts CSE 2102 Interface Interaction With the Outer World Signature + Requested Services Type: Abstract Entity - Interface + Semantics Subtype: Inherits the Supertype Definition Class: Implementation of a Type Realization: Relation Between a Type and a Class That Implements It Subclass: Inherits the Superclass Implementation Instance: Element of a Class 50 UML Diagrammatic Representations CSE 2102 Component Diagram: Captures the Physical Structure of the Implementation Deployment Diagram: Captures the Topology of a System’s Hardware Collaboration Diagram: Captures Dynamic Behavior (Message-Oriented) What About Other Diagrams? State Chart Diagram: Captures Dynamic Behavior (Event-Oriented) Activity Diagram: Captures Dynamic Behavior (Activity-Oriented) These and Others Seem too Low Level … What is Role of UML for BMI? Yet Another Design Artifact Can it be More? 51 Component Diagram CSE 2102 Captures the Physical Structure of the Implementation 52 Deployment Diagram CSE 2102 Captures the Topology of a System’s Hardware 53 Collaboration Diagram CSE CSE 2102 2102 54 Single and Multi-Tier Architectures CSE 2102 Widespread use in Practice for All Types of Distributed Systems and Applications Two Kinds of Components Servers: Provide Services - May be Unaware of Clients Web Servers (unaware?) Database Servers and Functional Servers (aware?) Clients: Request Services from Servers Must Identify Servers May Need to Identify Self A Server Can be Client of Another Server Expanding from Micro-Architectures (Single Computer/One Application) to Macro-Architecture 55 Single and Multi-Tier Architectures CSE 2102 Normally, Clients and Servers are Independent Processes Running in Parallel Connectors Provide Means for Service Requests and Answers to be Passes Among Clients/Servers Connectors May be RPC, RMI, etc. Advantages Parallelism, Independence Separation of Concerns, Abstraction Others? Disadvantages Complex Implementation Mechanisms Scalability, Correctness, Real-Time Limits Others? 56 Example: Software Architectural Structure CSE CSE 2102 2102 Initial Data Entry Operator (Scanning & Posting) Advanced Data Entry Operators Analyst Manager 10-100MB Network Document Server Stored Images/CD Database Server Running Oracle RMI Registry RMI Act. Obj/Server RMI Act. Obj/Server Functional Server 57 Business Process Model CSE CSE 2102 2102 DB DB Historical Completed Records Applications Licensing DB Supervisor Review Scanner DB Licensing Division Scanning Operator Stored Images Licensing Division Printer Data Entry Operator DB Basic Information Entered New Licenses New Appointments FOI Letters (Request Information, etc.) 58 Two-Tier Architecture CSE 2102 Small Manufacturer Previously on C++ New Order Entry, Inventory, and Invoicing Applications in Java Programming Language Existing Customer and Order Database Most of Business Logic in Stored Procedures Tool-generated GUI Forms for Java Objects 59 Three-Tier Architecture CSE 2102 Passenger Check-in for Regional Airline Local Database for Seating on Today's Flights Clients Invoke EJBs at Local Site Through RMI EJBs Update Database and Queue Updates JMS Queues Updates to Legacy System DBC API Used to Access Local Database 60 Four-Tier Architecture CSE 2102 Web Access to Brokerage Accounts Only HTML Browser Required on Front End "Brokerbean" EJB Provides Business Logic Login, Query, Trade Servlets Call Brokerbean Use JNDI to Find EJBs, RMI to Invoke Them 61 Architecture Comparisons CSE 2102 Two-tier Through JDBC API is Simplest Multi-tier: Separate Business Logic, Protect Database Integrity, More Scaleable JMS Queues vs. Synchronous (RMI or IDL): Availability, Response Time, Decoupling JMS Publish & Subscribe: Off-line Notification RMI IIOP vs. JRMP vs. Java IDL: Standard Cross-language Calls or Full Java Functionality JTS: Distributed Integrity, Lockstep Actions 62 Comments on Architectural Styles CSE 2102 Architectural Styles Provide Patterns Suppose Designing a New System During Requirements Discovery, Behavior and Structure of System Will Emerge Attempt to Match to Architectural Style Modify, Extend Style as Needed By Choosing Existing Architectural Style Know Advantages and Disadvantages Ability to Focus in on Problem Areas and Bottlenecks Can Adjust Architecture Accordingly Architectures Range from Large Scale to Small Scale in their Applicability We’ll see Examples for BMI Shortly … 63 The Next Big Challenge CSE 2102 Macro-Architectures System of Systems Application of Applications Involves Two Key Issues Interoperability Heterogeneous Distributed Databases Heterogeneous Distributed Systems Autonomous Applications Scalability Rapid and Continuous Growth Amount of Data Variety of Data Types Different Privacy Levels or Ownerships of Data 64 Interoperability: A Classic View CSE CSE 2102 2102 Local Schema Simple Federation Multiple Nested Federation FDB Global Schema FDB Global Schema 4 Federated Integration Federated Integration Local Schema Local Schema FDB 1 Local Schema Federation FDB3 Federation 65 What is CORBA? CSE 2102 Differs from Typical Programming Languages Objects can be … Located Throughout Network Interoperate with Objects on other Platforms Written in Ant PLs for which there is mapping from IDL to that Language Application Interfaces Domain Interfaces Object Request Broker Object Services 66 What is CORBA? CSE 2102 Allow Interactions from Client to Server CORBA Installed on All Participating Machines Client Application Static Stub DII Server Application ORB Interface ORB Interface Skel eton DSI Object Adapter Client ORB Core Network IDL - Independent Same for all applications Server ORB Core There may be multiple object adapters 67 CORBA-Based Development CSE CSE 2102 2102 IDL file Client Application IDL Compiler Stub ORB/IIOP Object Implementation IDL Compiler Skeleton ORB/IIOP 68 Database Interoperability in the Internet CSE 2102 Technology Web/HTTP, JDBC/ODBC, CORBA (ORBs + IIOP), XML Architecture Information Broker •Mediator-Based Systems •Agent-Based Systems 69 ORB Integration:Java Client + Legacy Application CSE CSE 2102 2102 Java Client Legacy Application Java Wrapper Object Request Broker (ORB) CORBA is the Medium of Info. Exchange Requires Java/CORBA Capabilities 70 Java Client with Wrapper to Legacy Application CSE CSE 2102 2102 Java Client Java Application Code WRAPPER Mapping Classes JAVA LAYER Interactions Between Java Client and Legacy Appl. via C and RPC C is the Medium of Info. Exchange Java Client with C++/C Wrapper NATIVE LAYER Native Functions (C++) RPC Client Stubs (C) Legacy Application Network 71 COTS and Legacy Appls. to Java Clients CSE CSE 2102 2102 COTS Application Java Application Code Legacy Application Java Application Code Native Functions that Map to COTS Appl NATIVE LAYER Native Functions that Map to Legacy Appl NATIVE LAYER JAVA LAYER JAVA LAYER Mapping Classes JAVA NETWORK WRAPPER Mapping Classes JAVA NETWORK WRAPPER Network Java Client Java Client Java is Medium of Info. Exchange - C/C++ Appls with Java Wrappers 72 Java Client to Legacy App via RDBS CSE CSE 2102 2102 Transformed Legacy Data Java Client Updated Data Relational Database System(RDS) Extract and Generate Data Transform and Store Data Legacy Application 73 JDBC CSE 2102 JDBC API Provides DB Access Protocols for Open, Query, Close, etc. Different Drivers for Different DB Platforms JDBC API Java Application Driver Manager Driver Oracle Driver Access Driver Driver Sybase 74 Connecting a DB to the Web CSE CSE 2102 2102 DBMS CGI Script Invocation or JDBC Invocation Web Server Web Server are Stateless DB Interactions Tend to be Stateful Invoking a CGI Script on Each DB Interaction is Very Expensive, Mainly Due to the Cost of DB Open Internet Browser 75 Connecting More Efficiently CSE CSE 2102 2102 DBMS Helper Processes CGI Script or JDBC Invocation Web Server Internet To Avoid Cost of Opening Database, One can Use Helper Processes that Always Keep Database Open and Outlive Web Connection Newly Invoked CGI Scripts Connect to a Preexisting Helper Process System is Still Stateless Browser 76 DB-Internet Architecture CSE CSE 2102 2102 WWW Client (Netscape) WWW client (Info. Explore) WWW Client (HotJava) Internet HTTP Server DBWeb Gateway DBWeb Gateway DBWeb Gateway DBWeb Dispatcher DBWeb Gateway 77 Internet and the Web CSE 2102 A Major Opportunity for Business A Global Marketplace Business Across State and Country Boundaries A Way of Extending Services Online Payment vs. VISA, Mastercard A Medium for Creation of New Services Publishers, Travel Agents, Teller, Virtual Yellow Pages, Online Auctions … A Boon for Academia Research Interactions and Collaborations Free Software for Classroom/Research Usage Opportunities for Exploration of Technologies in Student Projects What are Implications for BMI? Where is the Adv? 78 WWW: Three Market Segments CSE CSE 2102 2102 Server Business to Business Corporate Network Server Intranet Decision support Mfg.. System monitoring corporate repositories Workgroups Internet Internet Provider Network Information sharing Ordering info./status Targeted electronic commerce Corporate Server Network Sales Marketing Information Services Server Provider Network Exposure to Outside 79 Information Delivery Problems on the Net CSE 2102 Everyone can Publish Information on the Web Independently at Any Time Consequently, there is an Information Explosion Identifying Information Content More Difficult There are too Many Search Engines but too Few Capable of Returning High Quality Data Most Search Engines are Useful for Ad-hoc Searches but Awkward for Tracking Changes What are Information Delivery Issues for BMI? Publishing of Patient Education Materials Publishing of Provider Education Materials How Can Patients/Providers find what Need? How do they Know if its Relevant? Reputable? 80 Example Web Applications CSE 2102 Scenario 1: World Wide Wait A Major Event is Underway and the Latest, Up-tothe Minute Results are Being Posted on the Web You Want to Monitor the Results for this Important Event, so you Fire up your Trusty Web Browser, Pointing at the Result Posting Site, and Wait, and Wait, and Wait … What is the Problem? The Scalability Problems are the Result of a Mismatch Between the Data Access Characteristics of the Application and the Technology Used to Implement the Application 81 Example Web Applications CSE 2102 Scenario 2: Many Applications Today have the Need for Tracking Changes in Local and Remote Data Sources and Notifying Changes If Some Condition Over the Data Source(s) is Met To Monitor Changes on Web, You Need to Fire Your Trusty Web Browser from Time to Time, Cache the Most Recent Result, and Difference Manually Each Time You Poll the Data Source(s) Issue: Pure Pull is Not the Answer to All Problems 82 What is the Problem? CSE 2102 Applications are Asymmetric but the Web is Not Computation Centric vs. Information Flow Centric Type of Asymmetry Network Asymmetry Satellite, CATV, Mobile Clients, Etc. Client to Server Ratio Too Many Clients can Swamp Servers Data Volume Mouse and Key Click vs. Content Delivery Update and Information Creation Clients Need to be Informed or Must Poll 83 What are Information Delivery Styles? CSE 2102 Pull-Based System Transfer of Data from Server to Client is Initiated by a Client Pull Clients Determine when to Get Information Potential for Information to be Old Unless Client Periodically Pulls Push-Based System Transfer of Data from Server to Client is Initiated by a Server Push Clients may get Overloaded if Push is Too Frequent Hybrid Pull and Push Combined Pull First and then Push Continually 84 Publish/Subscribe CSE 2102 Semantics: Servers Publish/Clients Subscribe Servers Publish Information Online Clients Subscribe to the Information of Interest (Subscription-based Information Delivery) Data Flow is Initiated by the Data Sources (Servers) and is Aperiodic Danger: Subscriptions can Lead to Other Unwanted Subscriptions Applications Unicast: Database Triggers and Active Databases 1-to-n: Online News Groups May work for Clinical Researcher to Provider Push 85 Design Options for Nodes CSE 2102 Three Types of Nodes: Data Sources Provide Base Data which is to be Disseminated Clients Who are the Net Consumers of the Information Information Brokers Acquire Information from Other Data Sources, Add Value to that Information and then Distribute this Information to Other Consumers By Creating a Hierarchy of Brokers, Information Delivery can be Tailored to the Need of Many Users Brokers may be Ideal Intermediaries for BMI! Act on Behalf of Patients, Providers Incorporate Secure Access 86 CSE 2102 Research Challenges Ubiquitous/Pervasive Many computers and information appliances everywhere, networked together Inherent Complexity: Coping with Latency (Sometimes Unpredictable) Failure Detection and Recovery (Partial Failure) Concurrency, Load Balancing, Availability, Scale Service Partitioning Ordering of Distributed Events “Accidental” Complexity: Heterogeneity: Beyond the Local Case: Platform, Protocol, Plus All Local Heterogeneity in Spades. Autonomy: Change and Evolve Autonomously Tool Deficiencies: Language Support (Sockets,rpc), Debugging, Etc. 87 Infosphere CSE CSE 2102 2102 Problem: too many sources,too much information Internet: Information Jungle Infopipes Clean, Reliable, Timely Information, Anywhere Digital Earth Personalized Filtering & Info. Delivery Sensors 88 Current State-of-Art CSE CSE 2102 2102 Web Server Mainframe Database Server Thin Client 89 Infosphere Scenario CSE CSE 2102 2102 Infotaps & Fat Clients Sensors Variety of Servers Many sources Database Server 90 Heterogeneity and Autonomy CSE 2102 Heterogeneity: How Much can we Really Integrate? Syntactic Integration Different Formats and Models Web/SQL Query Languages Semantic Interoperability Basic Research on Ontology, Etc Autonomy No Central DBA on the Net Independent Evolution of Schema and Content Interoperation is Voluntary Interface Technology (Support for Isvs) DCOM: Microsoft Standard CORBA, Etc... 91 Security and Data Quality CSE 2102 Security System Security in the Broad Sense Attacks: Penetrations, Denial of Service System (and Information) Survivability Security Fault Tolerance Replication for Performance, Availability, and Survivability Data Quality Web Data Quality Problems Local Updates with Global Effects Unchecked Redundancy (Mutual Copying) Registration of Unchecked Information Spam on the Rise 92 Legacy Data Challenge CSE 2102 Legacy Applications and Data Definition: Important and Difficult to Replace Typically, Mainframe Mission Critical Code Most are OLTP and Database Applications Evolution of Legacy Databases Client-server Architectures Wrappers Expensive and Gradual in Any Case 93 Electronic Medical Record Architectures CSE 2102 Provider-Based Systems have Two Variants All Data In House Limited In House – Off Site Storage (Larger, Multi-Site Practices Larger Providers (Clinics) Control All Own Data Sizeable IT Staff for 24-7 Operations Control of Own Backups Smaller Providers – Limited IT Staff Desire Out-of-Box Solution Local Data for Ease of Access Remote Storage – Promotes Off-Hours Access Even 1st Variant – Service for “Backups” 94 Key Challenges to Integrating Data CSE 2102 Security and Privacy PHI and PII HIPAA FERPA WIC, Social Security (Medicaid/Medicare) regulations State statutes Alteration/disruption of business practices Unique identification of individuals/cases Accuracy and reliability of data Disparate hardware/software platforms 95 EMR for Large Providers - AllScript CSE CSE 2102 2102 96 EMR for Smaller Providers CSE CSE 2102 2102 Provider’s Office Local EMR Vendor’s Location Server/Data Farm Patient Data Remote EMR Remote Access 97 Integrating Clinical Repositories CSE 2102 Provider/Hospital Relationship Provider has Privileges at Hospital Provider Chooses Office-Based EMR More Easily Integrated with Hospital EMR Emerging at Community Hospital Level Example: Milford Hospital, MA All Area Providers with Privileges Linked in Ability to See Patient Records, Tests, at Hospital Unclear on Uploads from Providers to Hospital However, No Link to UMass Medical Center (of which Milford Hospital is Affiliated) 98 Integrating Clinical Repositories CSE 2102 99 Integrating Clinical Repositories CSE CSE 2102 2102 100 Integrating Clinical Repositories CSE CSE 2102 2102 101 Integrating Clinical Repositories CSE CSE 2102 2102 NHIN Prototype Phase I 102 Integrating Clinical Repositories CSE CSE 2102 2102 NHIN Prototype Phase II 103 CSE 2102 104