David W Chang

US Patent:

6397383, May 28, 2002

Filed:

Feb 26, 1999

Appl. No.:

09/259176

Inventors:

David Yu Chang - Austin TX
Ajay Reddy Karkala - Austin TX
John Shih-Yuan Wang - Austin TX

Assignee:

International Business Machines Corp. - Armonk NY

International Classification:

G06F 945

US Classification:

717142, 717143, 707 3, 707 4, 707 6

Abstract:

The present invention provides a system and method for parsing a constraint language in a computer network. The method includes receiving a constraint string; parsing the constraint string, comprising replacement of valid operators, variables, and values with special characters; and determining if the parsed constraint string indicates the existence of errors in the constraint string. The parser of the present invention is based upon an analysis of the constraint language from which patterns of the language are identified. The easily implemented parser of the present invention is developed based on these patterns. Because the method of the present invention replaces members of a finite set of valid operators, variables, and values, instead of attempting to identify an infinite number of possible errors, it is able to detect all invalid constraints.

US Patent:

6687831, Feb 3, 2004

Filed:

Apr 29, 1999

Appl. No.:

09/303366

Inventors:

Virgil Anthony Albaugh - Austin TX
Messaoud Benantar - Austin TX
John Alexander Buslawski - Austin TX
David Yu Chang - Austin TX

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1100

US Classification:

713201, 709227

Abstract:

A method and apparatus in a computer system for establishing a connection between a client proxy object and a server target object. A request is received from the client proxy object to access the server target object, wherein the request includes an identification of a type of communication and type of message to be sent to the server target object. A connection object is identified based on the type of communication and the type of message. The connection object implementing the type of communication is returned, wherein the connection between the client proxy object and the server target object is facilitated using the connection object.

US Patent:

6704765, Mar 9, 2004

Filed:

Dec 14, 1994

Appl. No.:

08/355885

Inventors:

David Yu Chang - Austin TX
George Prentice Copeland - Austin TX
Ambuj Goyal - Amawalk NY
Marc Gregory Smith - Austin TX

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 900

US Classification:

709102

Abstract:

A certain number of agents and tokens are created. A first agent that is assigned a request must obtain a token to process the request. The number of agents which may concurrently process requests are limited by preventing an agent from processing a request unless the agent has an assigned token. An additional agent is created after assigning the token to the first agent, provided that an existing agent is not available to wait for a request, and an unassigned token is available for the additional agent. A certain minimum number of agents is defined and an agent is automatically eliminated when the agent completes a request, provided that the number of agents that are assigned tokens exceeds the minimum number of agents.

US Patent:

6898717, May 24, 2005

Filed:

Jul 20, 2000

Appl. No.:

09/620728

Inventors:

John Alexander Buslawski - Austin TX, US
David Yu Chang - Austin TX, US
Derek Wan Hok Ho - Austin TX, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H04L009/00
G06F015/16

US Classification:

713201, 709223

Abstract:

A method and implementing computer system are provided in which a Quality Of Protection (QOP) indication is established in a tagged component for servers in a network domain. Each server may have one QOP setting associated with the server for inbound messages and another QOP setting associated with the server for outbound messages. In an exemplary embodiment, the QOP settings are contained in a list which may be updated to include additional QOPs which the server may be equipped to support.

US Patent:

6912718, Jun 28, 2005

Filed:

Mar 25, 1999

Appl. No.:

09/276382

Inventors:

David Yu Chang - Austin TX, US
John Shih-Yuan Wang - Austin TX, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F003/00
G06F009/44
G06F009/46
G06F013/00

US Classification:

719318, 719313, 719314, 719315, 719316

Abstract:

An event notification channel is provided in a computer controlled object oriented programming system having at least one event supplier object and a plurality of event consumer objects which may be run continuously without interruption and without loss of event notification to any consumer object irrespective of whether any of the consumer objects are off line for filter modification or any other maintenance purpose. The channel transmits events from supplier objects to a plurality of filter objects, each respectively associated with one of the plurality of consumer objects for passing only selected events to the associated consumer object. The system includes a plurality of proxy consumer objects, each associated with one of said consumer objects and between said filter object and said supplier object, whereby said proxy consumer object may receive supplier transmitted events on behalf of its associated consumer object. Thus, where the actual consumer object is off line for filter modification, the proxy will remain in the system and receive the transmitted events.

US Patent:

6950825, Sep 27, 2005

Filed:

May 30, 2002

Appl. No.:

10/159482

Inventors:

David Yu Chang - Austin TX, US
Ching-Yun Chao - Austin TX, US
Hyen Vui Chung - Round Rock TX, US
Carlton Keith Mason - Austin TX, US
Vishwanath Venkataramappa - Austin TX, US
Leigh Allen Williamson - Austin TX, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F017/30

US Classification:

707100, 707 10, 707103, 707 9, 709203, 709225

Abstract:

A security policy process which provides role-based permissions for hierarchically organized system resources such as domains, clusters, application servers, and resources, as well as topic structures for messaging services. Groups of permissions are assigned to roles, and each user is assigned a role and a level of access within the hierarchy of system resources or topics. Forward or reverse inheritance is applied to each user level-role assignment such that each user is allowed all permissions for ancestors to the assigned level or descendants to the assigned level. This allows simplified security policy definition and maintenance of user permissions as each user's permission list must only be configured and managed at one hierarchical level with one role.

US Patent:

6996620, Feb 7, 2006

Filed:

Jan 9, 2002

Appl. No.:

10/042495

Inventors:

David Yu Chang - Austin TX, US
Derek Wan Hok Ho - Austin TX, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 13/00

US Classification:

709227, 709219, 709225

Abstract:

A system and method for concurrent security connections is presented. An association table is used that includes a list of active credentials. An active credential includes information such as user id and password information for a given domain. The active credential may also include dynamic data that is retrieved from a user, such as a pseudo-random code or a fingerprint scan. The active credential is sent to a domain, or the managing server of the domain, when domain access is requested. This access request does not involve the user of the client unless dynamic input data is requested.

US Patent:

7076798, Jul 11, 2006

Filed:

Feb 7, 2002

Appl. No.:

10/068335

Inventors:

David Yu Chang - Austin TX, US
Nataraj Nagaratnam - Morrisville NC, US
Russell Ley Newcombe - Round Rock TX, US
Lori Jane Milhans VanGulick - Cedar Park TX, US
Vishwanath Venkataramappa - Austin TX, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H04L 9/32

US Classification:

726 4, 726 28, 713167, 709219, 709229, 719330

Abstract:

A method and system for providing security protection to Common Object Request Broker Architecture (CORBA) objects located on a server. An EJB shadow object is created for the CORBA object. The EJB shadow object invokes an EJB security mechanism on behalf of the CORBA object, thus protecting the CORBA object from unauthorized object requesters. In a preferred embodiment, requesters are categorized and identified by their roles in the enterprise. Only those requesters having a proper role are authorized to access the requested object.