Compiler-Assisted Scheduling for Real-Time Applications: A Static Alternative to Low-Level Tuning

Developing a real-time system requires finding a balance between the timing constraints and the functional requirements. Achieving this balance often requires last-minute, low-level intervention in the code modules -- via intensive hardware-based instrumentation and manual program optimizations. In this dissertation we present an automated, static alternative to this kind of human-intensive work. Our approach is motivated by recent advances in compiler technologies, which we extend to two specific issues on real-time programming, that is, feasibility and schedulability. A task is infeasible if its execution time stretches over its deadline. To eliminate such faults, we have developed a synthesis method that (1) inspects all infeasible paths, and then (2) moves instructions out of those paths to shorten the execution time. On the other hand, schedulability of a task set denotes an ability to guarantee the deadlines of all tasks in the application. This property is affected by interactions between the tasks, as well as their individual execution times and deadlines. To address the schedulability problem, we have developed a task transformation method based on program slicing. The method decomposes a task into two subthreads: the IO-handler component that must meet the original deadline, and the state-update component that can be postponed past the deadline. This delayed-deadline approach contributes to the schedulability of the overall application. We also present a new fixed-priority preemptive scheduling strategy, which yields both a feasible priority ordering and a feasible task-slicing metric. (Also cross-referenced as UMIACS-TR-95-33

Compiling Real-Time Programs with Timing Constraint Refinement and Structural Code Motion

We present a programming language called TCEL (Time-Constrained Event Language), whose semantics is based on time-constrained relationships between observable events. Such a semantics infers only those timing constraints necessary to achieve real-time correctness, without over-constraining the system. Moreover, an optimizing compiler can exploit this looser semantics to help tune the code, so that its worst-case execution time is consistent with its real-time requirements. In this paper we describe such a transformation system, which works in two phases. First the TCEL source code is translated into an intermediate representation. Then an instruction-scheduling algorithm rearranges selected unobservable operations, and synthesizes tasks guaranteed to respect the original event-based constraints. (Also cross-referenced as UMIACS-TR-94-90

Design of PC beam-column joint applied X-braced bars in the segmented structural system

This study suggests a joint design using an X-brace bar to identify the stability and structural performance of a precast concrete (PC) beam-column joint design, which may cause problems when used in a segmented PC beam system for a long-span structure. For this, an experimental PC beam-column model at half scale was designed and veri­fied for applicability of X-braced bars in a panel zone. While previous studies suggested the development of a long-span structural system using precast concrete (PC) and described the problems with PC beam-column joints, this study proposes a solution to improve the structural stability and performance of a PC beam-column joint design and conducts analytical verification

End-to-End Design of Real-Time Systems

(Also cross-referenced as UMIACS-TR-95-61

Per-Client Network Performance Isolation in VDE-based Cloud Computing Servers

Authors' final versionIn a cloud server where multiple virtual machines owned by different clients are cohosted, excessive traffic generated by a small group of clients may well jeopardize the quality of service of other clients. It is thus very important to provide per-client network performance isolation in a cloud computing environment. Unfortunately, the existing techniques are not effective enough for a huge cloud computing system since it is difficult to adopt them in a large scale and they often require non-trivial modification to the established network protocols. To overcome such difficulties, we propose per-client network performance isolation using VDE (Virtual Distributed Ethernet) as a base framework. Our approach begins with per-client weight specification and support client-aware fair share scheduling and packet dispatching for both incoming and outgoing traffic. It also provides hierarchical fairness between a client and its virtual machines. Our approach supports full virtualization of a guest OS, wide scale adoption, limited modification to the existing system, low run-time overhead and work-conserving servicing. Our experimental results show the effectiveness of the proposed approach. Every client received at least 99.4% of its bandwidth share as specified by its weight.OAIID:oai:osos.snu.ac.kr:snu2012-01/102/0000004193/4SEQ:4PERF_CD:SNU2012-01EVAL_ITEM_CD:102USER_ID:0000004193ADJUST_YN:NEMP_ID:A005174DEPT_CD:4541CITE_RATE:.175FILENAME:11-12-23 JISE-VDE.pdfDEPT_NM:전기·컴퓨터공학부EMAIL:[email protected]_YN:YCONFIRM:

Evaluation of the TEST 1 erythrocyte sedimentation rate system and intra- and inter-laboratory quality control using new latex control materials

Background: The erythrocyte sedimentation rate (ESR) test has been considered to be a simple procedure, not requiring quality control (QC). However, QC is essential for accuracy and precision. We evaluated the TEST 1 ESR system and performed QC procedures using newly developed latex control materials in three hospitals. Methods: Using tripotassium ethylenediaminetetraacetic acid blood samples (n=184), we compared TEST 1 ESR values with Westergren ESR data and evaluated intra-assay precision. Three levels of latex control materials were used to assess inter-assay precision. Reference range assessment was done using samples from 220 healthy individuals. Inter-laboratory QC with latex control materials in three hospitals was performed. Results: Correlation between TEST 1 ESR and Westergren ESR results was good (p<0.001). Intra-assay precision [coefficients of variation (CV) 6.6%-21.7%] with patient samples and inter-assay precision (CV 0.0%-6.8%) with latex control materials were satisfactory. The reference ranges of 2-10 mm/h for males and 2-19 mm/h for females were established. Inter-laboratory QC data with latex control materials in three hospitals demonstrated good accuracy and satisfactory precision (CV 0.0%-14.4%). Conclusions: Our results demonstrate that the TEST 1 QC is reliable and the latex control materials are valuable for inter-laboratory proficiency testing. Clin Chem Lab Med 2010; 48: 1043-8.Cha CH, 2009, AM J CLIN PATHOL, V131, P189, DOI 10.1309/AJCPOU1ASTLRANIJ*CLIN LAB STAND I, 2008, C28A3 CLSIPiva E, 2007, CLIN BIOCHEM, V40, P491, DOI 10.1016/j.clinbiochem.2006.12.002Padro-Miquel A, 2007, CLIN CHEM LAB MED, V45, P930, DOI 10.1515/CCLM.2007.150Romero A, 2003, CLIN CHEM LAB MED, V41, P232Plebani M, 2002, AM J CLIN PATHOL, V117, P621LEE BH, 2002, J CLIN PATHOL QUALIT, V24, P167GIAVARINA D, 2002, CLIN LAB, V48, P459Piva E, 2001, CLIN CHEM LAB MED, V39, P451*CLIN LAB STAND I, 2000, H2A4 CLSIPlebani M, 1998, AM J CLIN PATHOL, V110, P334BULL BS, 1993, J CLIN PATHOL, V46, P198BULL BS, 1991, PRACTICAL LAB HEMATOFABRY TL, 1987, BLOOD, V70, P1572WESTERGREN A, 1926, AM REV TUBERC, V14, P94

Mutations in DDX58, which Encodes RIG-I, Cause Atypical Singleton-Merten Syndrome

Singleton-Merten syndrome (SMS) is an autosomal-dominant multi-system disorder characterized by dental dysplasia, aortic calcification, skeletal abnormalities, glaucoma, psoriasis, and other conditions. Despite an apparent autosomal-dominant pattern of inheritance, the genetic background of SMS and information about its phenotypic heterogeneity remain unknown. Recently, we found a family affected by glaucoma, aortic calcification, and skeletal abnormalities. Unlike subjects with classic SMS, affected individuals showed normal dentition, suggesting atypical SMS. To identify genetic causes of the disease, we performed exome sequencing in this family and identified a variant (c.1118A>C [p.Glu373Ala]) of DDX58, whose protein product is also known as RIG-I. Further analysis of DDX58 in 100 individuals with congenital glaucoma identified another variant (c.803G>T [p.Cys268Phe]) in a family who harbored neither dental anomalies nor aortic calcification but who suffered from glaucoma and skeletal abnormalities. Cys268 and Glu373 residues of DDX58 belong to ATP-binding motifs I and II, respectively, and these residues are predicted to be located closer to the ADP and RNA molecules than other nonpathogenic missense variants by protein structure analysis. Functional assays revealed that DDX58 alterations confer constitutive activation and thus lead to increased interferon (IFN) activity and IFN-stimulated gene expression. In addition, when we transduced primary human trabecular meshwork cells with c.803G>T (p.Cys268Phe) and c.1118A>C (p.Glu373Ala) mutants, cytopathic effects and a significant decrease in cell number were observed. Taken together, our results demonstrate that DDX58 mutations cause atypical SMS manifesting with variable expression of glaucoma, aortic calcification, and skeletal abnormalities without dental anomalies

Mutations in DDX58, which Encodes RIG-I, Cause Atypical Singleton-Merten Syndrome

Singleton-Merten syndrome (SMS) is an autosomal-dominant multi-system disorder characterized by dental dysplasia, aortic calcification, skeletal abnormalities, glaucoma, psoriasis, and other conditions. Despite an apparent autosomal-dominant pattern of inheritance, the genetic background of SMS and information about its phenotypic heterogeneity remain unknown. Recently, we found a family affected by glaucoma, aortic calcification, and skeletal abnormalities. Unlike subjects with classic SMS, affected individuals showed normal dentition, suggesting atypical SMS. To identify genetic causes of the disease, we performed exome sequencing in this family and identified a variant (c.1118A>C [p.GLu373Ala]) of DDX58, whose protein product is also known as RIG-I. Further analysis of DDX58 in 100 individuals with congenital glaucoma identified another variant (c.803G>T [p.Cys268Phe]) in a family who harbored neither dental anomalies nor aortic calcification but who suffered from glaucoma and skeletal abnormalities. Cys268 and Glu373 residues of DDX58 belong to ATP-binding motifs I and II, respectively, and these residues are predicted to be located closer to the ADP and RNA molecules than other nonpathogenic missense variants by protein structure analysis. Functional assays revealed that DDX58 alterations confer constitutive activation and thus lead to increased interferon (IFN) activity and IFN-stimulated gene expression. In addition, when we transduced primary human trabecular meshwork cells with c.803G>T (p.Cys268Phe) and c.1118A>C (p.Glu373A1a) mutants, cytopathic effects and a significant decrease in cell number were observed. Taken together, our results demonstrate that DDX58 mutations cause atypical SMS manifesting with variable expression of glaucoma, aortic calcification, and skeletal abnormalities without dental anomalies.X116452Ysciescopu

A common variant near TGFBR3 is associated with primary open angle glaucoma

Primary open angle glaucoma (POAG), a major cause of blindness worldwide, is a complex disease with a significant genetic contribution. We performed Exome Array (Illumina) analysis on 3504 POAG cases and 9746 controls with replication of the most significant findings in 9173 POAG cases and 26 780 controls across 18 collections of Asian, African and European descent. Apart from confirming strong evidence of association at CDKN2B-AS1 (rs2157719 [G], odds ratio [OR] = 0.71, P = 2.81 × 10−33), we observed one SNP showing significant association to POAG (CDC7–TGFBR3 rs1192415, ORG-allele = 1.13, Pmeta = 1.60 × 10−8). This particular SNP has previously been shown to be strongly associated with optic disc area and vertical cup-to-disc ratio, which are regarded as glaucoma-related quantitative traits. Our study now extends this by directly implicating it in POAG disease pathogenesis