Jong Hyuk Choi

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We present a new arrangement of directory bits called the segment directory to improve directory storage efficiency: a segment directory can point to several sharing processors with almost the same number of bits as the pointer which can point to only one. Many directory overflows can be eliminated by using the segment directory element in place of the(More)
— Directory is a specialized data store optimized for efficient information retrieval which has standard information model, naming scheme, and access protocol for interoperability over network. It stores critical data such as user, resource, and policy information in the enterprise computing environment. This paper presents a performance driven design of a(More)
Lightweight Directory Access Protocol (LDAP) is the predominant Internet directory access protocol and hence so is its use in the Public Key Infrastructure (PKI). This paper presents the design and implementation of LDAP component matching which enhances flexibility and security of the LDAP directory service when it is used for the PKI certificate(More)
Commercial scale-out is a new research project at IBM research. Its main goal is to investigate and develop technologies for the use of large scale parallelism in commercial applications, eventually leading to a commercial supercomputer. The project leverages and explores the features of IBM's BladeCenter family of products. A significant challenge in using(More)
This paper presents a mesh with virtual buses as the bandwidth-efficient implementation of the mesh with multiple broadcasting on which many computational problems can be solved with reduced time complexity. The new system provides a low latency and high bandwidth communication mechanism without the disadvantage of the dual network approach: the possible(More)
As an integral part of the Web Services Security (WS-Security), directory services are used to store and access X.509 certificates. Lightweight Directory Access Protocol (LDAP) is the predominant directory access protocol for the Internet, and hence for the Web services. Values of LDAP attribute and assertion value syntaxes, though defined using ASN.1, are(More)
Most cases of Middle East Respiratory Syndrome (MERS) infection in Korea (outbreak: May 11-July 4, 2015) occurred in hospital settings, with uncertain transmission modes in some cases. We performed an in-depth investigation epidemiological survey on the 178th case to determine the precise mode of transmission. A 29- year-old man living in Pyeongtaek(More)
Since the first case was diagnosed on May 20, 2015, there were 186 confirmed cases of Middle East Respiratory Syndrome (MERS) until the end of outbreak in South Korea. Although medical institutions were the most identifiable sources of MERS transmission in South Korea, similar to other countries, in-depth epidemiological investigation was required for some(More)
— Network routers for parallel enterprise servers need fault-tolerance as well as high performance to support a seamless value chain of e-business. This paper introduces a new cut-through flow control method, called the pathfinder, which provides an efficient restarting capability without the extra header delivery overhead for normal non-faulty routes. We(More)