The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Jeffrey L Collett - One of the best experts on this subject based on the ideXlab platform.
-
application of high performance anion exchange chromatography pulsed amperometric detection for measuring carbohydrates in routine daily filter samples collected by a national network 1 determination of the impact of biomass burning in the upper midw
Journal of Geophysical Research, 2011Co-Authors: Amy P Sullivan, N H Frank, Gretchen D Onstad, Christopher D Simpson, Jeffrey L CollettAbstract:[1] Biomass burning is one of the major sources of organic carbon aerosols. However, there is limited information on the temporal and spatial variability for the impact of biomass burning in most regions of the United States, including the upper Midwest. In an attempt to obtain information on these variabilities, high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was employed to measure the smoke marker levoglucosan (and various other carbohydrates) on archived daily Federal Reference Monitor (FRM) Teflon filter samples from the PM2.5 NAAQS compliance Monitoring network. Levoglucosan data, along with measurements of water-soluble organic carbon (WSOC) and potassium, from the analysis of FRM samples collected at 10 sites in the upper Midwest from March 2004 through February 2005 are presented. Results suggest that WSOC contains a substantial regional component, summer levoglucosan is dependent on both horizontal and vertical transport of fire emissions, and potassium revealed no clear pattern associated with biomass burning impacts. The contribution of organic carbon due to primary biomass burning particle emissions ranged on average from about 5 to 35%, suggesting that for this study in the upper Midwest, >50% of the WSOC is from secondary organic aerosol rather than biomass burning. In a second paper the results from the measurements of the other carbohydrates that HPAEC-PAD analysis can determine are discussed to investigate their sources and trends.
-
application of high performance anion exchange chromatography pulsed amperometric detection for measuring carbohydrates in routine daily filter samples collected by a national network 2 examination of sugar alcohols polyols sugars and anhydrosugars i
Journal of Geophysical Research, 2011Co-Authors: Amy P Sullivan, N H Frank, D M Kenski, Jeffrey L CollettAbstract:[1] Carbohydrate measurements of ambient samples can provide insights into the biogenic fraction of the organic carbon (OC) aerosol. However, lack of measurement on a routine basis limits data analysis. In a companion paper, 1 year of archived 1-in-6 day FRM (Federal Reference Monitor) filter samples from the PM2.5 NAAQS compliance Monitoring network collected at 10 sites in the upper Midwest were analyzed using high-performance anion-exchange chromatography with pulsed amperometric detection to determine the regional impact of biomass burning. Along with levoglucosan, 13 other carbohydrates were simultaneously measured, including two more anhydrosugars (mannosan and galactosan), five sugars (arabinose, galactose, glucose, mannose, xylose), and six sugar alcohols/polyols (glycerol, methyltetrols, threitol/erythritol, xylitol, sorbitol, mannitol). This paper focuses on the results from these carbohydrates in order to investigate their sources and trends both spatially and temporally. Mannosan, galactosan, arabinose, xylose, and threitol/erythritol all correlated with levoglucosan (R2 from 0.43 to 0.97), suggesting biomass burning as their main source. Glucose and mannitol exhibited higher concentrations in summer and at more southern sites, likely due to vegetation differences at the sites. Using mannitol, the contribution of spores to OC was found to be <1%. Methyltetrols were highly correlated with water-soluble OC (R2 from 0.63 to 0.95) and in higher concentrations at more eastern sites. This spatial pattern is possibly due to these sites being downwind of the high isoprene emission zones that occur in the western part of the Midwest from oak forests in the Ozarks and spruce forests in the northern lake states.
Thu D. Nguyen - One of the best experts on this subject based on the ideXlab platform.
-
Using Firewalls to Enforce Enterprise-wide Policies over Standard Client-Server Interactions
2008Co-Authors: T. Phan, Thu D. NguyenAbstract:Abstract — We propose and evaluate a novel framework for enforcing global coordination and control policies over message passing software components in enterprise computing environments. This framework combines the use of firewalls, both per-node software and dedicated firewalls, with an existing coordination and control system to enforce policies that, among other properties, are stateful and communal. The firewalls act as a set of distributed Reference Monitors that filter messages exchanged between the interacting software components. The coordination and control system coordinates the firewalls to enforce a specific set of policies, passing only messages allowed by these policies. Filtering decisions may be based on credentials presented to the coordination and control system as well as system state accumulated over time. This filtering approach decouples coordination and control from application implementation, allowing the coordination and control mechanism and application implementations to evolve independently of each other. We demonstrate the power of our framework by using it to specify and enforce an RBAC policy with delegation, revocation, and separation-of-duty over accesses to a cluster of NFS and SMB file servers without changing any client or server implementations. Measurements show that our framework imposes acceptable overheads when enforcing this policy. Index Terms — coordination and control, access control, Reference Monitor, firewall, communal policies, stateful policies I
-
enforcing enterprise wide policies over standard client server interactions
Symposium on Reliable Distributed Systems, 2005Co-Authors: Z He, T. Phan, Thu D. NguyenAbstract:We propose and evaluate a novel framework for enforcing global coordination and control policies over interacting software components in enterprise computing environments. This framework combines a per-node Reference Monitor with two existing coordination and control systems to enforce policies that, among other properties, are stateful and communal. Each Reference Monitor filters messages exchanged between the interacting software components similar to a firewall, passing only messages that are allowed by the policies in effect. This filtering approach decouples coordination and control from application implementation, allowing the coordination and control mechanism and application implementations to evolve independently of each other. We demonstrate the power of our framework by using it to specify and enforce an RBAC policy with delegation, revocation, and separation-of-duty over accesses to a cluster of NFS and SMB file servers without changing any client or server implementations. Measurements show that our framework imposes acceptable overheads when enforcing this policy.
Amy P Sullivan - One of the best experts on this subject based on the ideXlab platform.
-
application of high performance anion exchange chromatography pulsed amperometric detection for measuring carbohydrates in routine daily filter samples collected by a national network 1 determination of the impact of biomass burning in the upper midw
Journal of Geophysical Research, 2011Co-Authors: Amy P Sullivan, N H Frank, Gretchen D Onstad, Christopher D Simpson, Jeffrey L CollettAbstract:[1] Biomass burning is one of the major sources of organic carbon aerosols. However, there is limited information on the temporal and spatial variability for the impact of biomass burning in most regions of the United States, including the upper Midwest. In an attempt to obtain information on these variabilities, high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was employed to measure the smoke marker levoglucosan (and various other carbohydrates) on archived daily Federal Reference Monitor (FRM) Teflon filter samples from the PM2.5 NAAQS compliance Monitoring network. Levoglucosan data, along with measurements of water-soluble organic carbon (WSOC) and potassium, from the analysis of FRM samples collected at 10 sites in the upper Midwest from March 2004 through February 2005 are presented. Results suggest that WSOC contains a substantial regional component, summer levoglucosan is dependent on both horizontal and vertical transport of fire emissions, and potassium revealed no clear pattern associated with biomass burning impacts. The contribution of organic carbon due to primary biomass burning particle emissions ranged on average from about 5 to 35%, suggesting that for this study in the upper Midwest, >50% of the WSOC is from secondary organic aerosol rather than biomass burning. In a second paper the results from the measurements of the other carbohydrates that HPAEC-PAD analysis can determine are discussed to investigate their sources and trends.
-
application of high performance anion exchange chromatography pulsed amperometric detection for measuring carbohydrates in routine daily filter samples collected by a national network 2 examination of sugar alcohols polyols sugars and anhydrosugars i
Journal of Geophysical Research, 2011Co-Authors: Amy P Sullivan, N H Frank, D M Kenski, Jeffrey L CollettAbstract:[1] Carbohydrate measurements of ambient samples can provide insights into the biogenic fraction of the organic carbon (OC) aerosol. However, lack of measurement on a routine basis limits data analysis. In a companion paper, 1 year of archived 1-in-6 day FRM (Federal Reference Monitor) filter samples from the PM2.5 NAAQS compliance Monitoring network collected at 10 sites in the upper Midwest were analyzed using high-performance anion-exchange chromatography with pulsed amperometric detection to determine the regional impact of biomass burning. Along with levoglucosan, 13 other carbohydrates were simultaneously measured, including two more anhydrosugars (mannosan and galactosan), five sugars (arabinose, galactose, glucose, mannose, xylose), and six sugar alcohols/polyols (glycerol, methyltetrols, threitol/erythritol, xylitol, sorbitol, mannitol). This paper focuses on the results from these carbohydrates in order to investigate their sources and trends both spatially and temporally. Mannosan, galactosan, arabinose, xylose, and threitol/erythritol all correlated with levoglucosan (R2 from 0.43 to 0.97), suggesting biomass burning as their main source. Glucose and mannitol exhibited higher concentrations in summer and at more southern sites, likely due to vegetation differences at the sites. Using mannitol, the contribution of spores to OC was found to be <1%. Methyltetrols were highly correlated with water-soluble OC (R2 from 0.63 to 0.95) and in higher concentrations at more eastern sites. This spatial pattern is possibly due to these sites being downwind of the high isoprene emission zones that occur in the western part of the Midwest from oak forests in the Ozarks and spruce forests in the northern lake states.
R S Ramakrishna - One of the best experts on this subject based on the ideXlab platform.
-
A Policy Language for the Extended Reference Monitor in Trusted Operating Systems
The Second International Conference on Availability Reliability and Security (ARES'07), 2007Co-Authors: R S Ramakrishna, Wook Shin, Koiuchi SakuraiAbstract:The main focus of current research in trusted operating systems (TOS) is on the enhanced access control of Reference Monitors which, in turn, control the individual operations on a given access instance. However, many real-life runtime attacks involve behavioral semantics. We have proposed an extended Reference Monitor to support both access and behavior controls. This results in a sequence of operations which are also of concern in security enforcement. This paper presents a policy language for the extended Reference Monitor. Our policy language is based on domain and type enforcement (DTE) and role-based access control (RBAC). Permission is defined as an event and a state of behavior is represented as a fluent to be accorded with the convention of event calculus (EC). Behavior policies can be expressed with the EC style syntax as well as access control policies
-
design and implementation of an extended Reference Monitor for trusted operating systems
Lecture Notes in Computer Science, 2006Co-Authors: Hyung Chan Kim, Wook Shin, R S Ramakrishna, Kouichi SakuraiAbstract:Conventional access control schemes have supported confidentiality and integrity acknowledging the necessary organizational security policy in operating systems. However, many runtime attacks in operating systems involve behavioral semantics, indicating that attacks should be seen as a sequence of access operations. Ironically these attacks are legitimate under any access control policy. This is due to the lack of behavioral dimension in security enforcement. We propose an extended Reference Monitor to include this dimension. Our method is based on safety property specification on system call sequences. The Reference Monitor checks the trace at runtime for behavior control in Linux operating system.
Koiuchi Sakurai - One of the best experts on this subject based on the ideXlab platform.
-
A Policy Language for the Extended Reference Monitor in Trusted Operating Systems
The Second International Conference on Availability Reliability and Security (ARES'07), 2007Co-Authors: R S Ramakrishna, Wook Shin, Koiuchi SakuraiAbstract:The main focus of current research in trusted operating systems (TOS) is on the enhanced access control of Reference Monitors which, in turn, control the individual operations on a given access instance. However, many real-life runtime attacks involve behavioral semantics. We have proposed an extended Reference Monitor to support both access and behavior controls. This results in a sequence of operations which are also of concern in security enforcement. This paper presents a policy language for the extended Reference Monitor. Our policy language is based on domain and type enforcement (DTE) and role-based access control (RBAC). Permission is defined as an event and a state of behavior is represented as a fluent to be accorded with the convention of event calculus (EC). Behavior policies can be expressed with the EC style syntax as well as access control policies
