Magnetic data are presented that indicate the VO3 array of the perovskite CeVO3 exhibits the same... more Magnetic data are presented that indicate the VO3 array of the perovskite CeVO3 exhibits the same anomalous properties as in LaVO3, including (1) a first-order magnetostrictive distortion below a Tt < TN, (2) a canted-spin ferromagnetism below TN, (3) a reversal of the direction of the vanadium atomic moments on traversing Tt, and (4) suppression of Tt in an isostructural
Localized-itinerant electronic transition in the perovskite system La 1-x Ca x VO 3. Hoan C. Nguy... more Localized-itinerant electronic transition in the perovskite system La 1-x Ca x VO 3. Hoan C. Nguyen and John B. Goodenough Center for Materials Science and Engineering, ETC 9.102, The University of Texas at Austin, Austin, Texas 78712-1063. Received 28 March 1995 ...
Magnetic studies of some orthovanadates. Hoan C. Nguyen and John B. Goodenough Center for Materia... more Magnetic studies of some orthovanadates. Hoan C. Nguyen and John B. Goodenough Center for Materials Science and Engineering, ETC 9.102, The University of Texas at Austin, Austin, Texas 78712-1063. Received 22 December 1994 ...
Rheumatoid arthritis affects millions of people all over the world. Up to 86% of cases involve ce... more Rheumatoid arthritis affects millions of people all over the world. Up to 86% of cases involve cervical spine alterations. Cervical spine instability patterns related to rheumatoid arthritis are: atlanto-axial subluxation, basilar invagination and subaxial instability. Once neurological deficit develops, progression can be fast and even lead to death. Rheumatoid arthritis treatment is mainly nonsurgical. Current medication and treatment protocols may prevent or delay the development of atlanto-axial disease. Periodical clinical and radiological examination help diagnose patients who already have neurological symptoms or those who are at risk of developing them, and who should thus be considered for surgical treatment. Preoperative neurological deficit is a predictor of postoperative neurological recovery, thus the importance of early detection and referral of patients at risk. Surgical treatment should be performed in specialized centers, by multidisciplinary groups. Along with early intervention, this should help reduce perioperative complications.
Abstract Previous research confirms the existence of recurring bug fixes in software systems. Ana... more Abstract Previous research confirms the existence of recurring bug fixes in software systems. Analyzing such fixes manually, we found that a large percentage of them occurs in code peers, the classes/methods having the similar roles in the systems, such as providing similar functions and/or participating in similar object interactions. Based on graph-based representation of object usages, we have developed several techniques to identify code peers, recognize recurring bug fixes, and recommend changes for code units from the bug ...
The interplay of multiple objects in object-oriented programming often follows specific protocols... more The interplay of multiple objects in object-oriented programming often follows specific protocols, for example certain orders of method calls and/or control structure constraints among them that are parts of the intended object usages. Unfortunately, the information is not always documented. That creates long learning curve, and importantly, leads to subtle problems due to the misuse of objects.
Geological and hydrogeological processes controlling recharge and the mobilization of As were inv... more Geological and hydrogeological processes controlling recharge and the mobilization of As were investigated in a shallow Holocene aquifer on the Red River flood plain near Hanoi, Vietnam. The geology was investigated using surface resistivity methods, geophysical borehole logging, drilling of boreholes and installation of more than 200 piezometers. Recharge processes and surface-groundwater interaction were studied using (i) time-series of hydraulic head distribution in surface water and aquifers, (ii) the stable isotope composition of waters and (iii) numerical groundwater modeling. The Red River and two of its distributaries run through the field site and control the groundwater flow pattern. For most of the year, there is a regional groundwater flow towards the Red River. During the monsoon the Red River water stage rises up to 6 m and stalls the regional groundwater flow. The two distributaries recharge the aquifer from perched water tables in the dry season, whilst in the flooding period surface water enters the aquifer through highly permeable bank sediments. The result is a dynamic groundwater flow pattern with rapid fluctuations in the groundwater table. A transient numerical model of the groundwater flow yields an average recharge rate of 60-100 mm/a through the confining clay, and a total recharge of approximately 200 mm/a was estimated from 3 H/ 3 He dating of the shallow groundwater. Thus in the model area, recharge of surface water from the river distributaries and recharge through a confining clay is of the same magnitude, being on average around 100 mm/a. The thickness of the confining clay varies between 2 and 10 m, and affects the recharge rate and the transport of electron acceptors (O 2 , NO À 3 and SO 2À 4 ) into the aquifer. Where the clay layer is thin, an up to 2 m thick oxic zone develops in the shallow aquifer. In the oxic zone the As concentration is less than 1 lg/L but increases in the reduced zone below to 550 lg/ L. In the Holocene aquifer, As is mobilized at a rate of around 14 lg/L/a. An As mass balance for the field site shows that around 1100 kg of As is annually leached from the Holocene sand and discharged into the Red River, corresponding to 0.01% of the total pool of As now present in the Holocene sand.
Code clone management has been shown to have several benefits for software developers. When sourc... more Code clone management has been shown to have several benefits for software developers. When source code evolves, clone management requires a mechanism to efficiently and incrementally detect code clones in the new revision. This paper introduces an incremental clone detection tool, called ClemanX. Our tool represents code fragments as subtrees of Abstract Syntax Trees (ASTs), measures their similarity levels based on their characteristic vectors of structural features, and solves the task of incrementally detecting similar code as an incremental distance-based clustering problem. Our empirical evaluation on large-scale software projects shows the usefulness and good performance of ClemanX.
However, there has been little work on clone detection in models with the limitations on detectio... more However, there has been little work on clone detection in models with the limitations on detection precision and completeness. This paper presents ModelCD, a novel clone detection tool for Matlab/Simulink models, that is able to efficiently and accurately detect both exactly matched and approximate model clones. The core of ModelCD is two novel graph-based clone detection algorithms that are able to systematically and incrementally discover clones with a high degree of completeness, accuracy, and scalability. We have conducted an empirical evaluation with various experimental studies on many real-world systems to demonstrate the usefulness of our approach and to compare the performance of ModelCD with existing tools.
Recent research results have shown more benefits of the management of code clones, rather than de... more Recent research results have shown more benefits of the management of code clones, rather than detecting and removing them. However, existing management approaches for code clone group evolution are still ad hoc, unsatisfactory, and limited. In this paper, we introduce a novel method for comprehensive code clone group management in evolving software. The core of our method is Cleman, an algorithmic framework that allows for a systematic construction of efficient and accurate clone group management tools. Clone group management is rigorously formulated by a formal model, which provides the foundation for Cleman framework. We use Cleman framework to build a clone group management tool that is able to detect high-quality clone groups and efficiently manage them when the software evolves. We also conduct an empirical evaluation on real-world systems to show the flexibility of Cleman framework and the efficiency, completeness, and incremental updatability of our tool.
Reusing existing library components is essential for reducing the cost of software development an... more Reusing existing library components is essential for reducing the cost of software development and maintenance. When library components evolve to accommodate new feature requests, to fix bugs, or to meet new standards, the clients of software libraries often need to make corresponding changes to correctly use the updated libraries. Existing API usage adaptation techniques support simple adaptation such as replacing the target of calls to a deprecated API, however, cannot handle complex adaptations such as creating a new object to be passed to a different API method, or adding an exception handling logic that surrounds the updated API method calls.
Page 1. 3784 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 58, NO. 9, SEPTEMBER 2011 A Novel ... more Page 1. 3784 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 58, NO. 9, SEPTEMBER 2011 A Novel Axial Flux Permanent-Magnet Machine for Flywheel Energy Storage System: Design and Analysis Trong Duy ...
Recent research results show several benefits of the management of code clones. In this paper, we... more Recent research results show several benefits of the management of code clones. In this paper, we introduce Clever, a novel clone-aware software configuration management (SCM) system. In addition to traditional SCM functionality, Clever provides clone management support, including clone detection and update, clone change management, clone consistency validating, clone synchronizing, and clone merging. Clever represents source code and clones as (sub)trees in Abstract Syntax Trees (ASTs), measures code similarity based on structural characteristic vectors, and describes code changes as tree editing scripts. The key techniques of Clever include the algorithms to compute tree editing scripts; to detect and update code clones and their groups; and to analyze the changes of cloned code to validate their consistency and recommend the relevant synchronization. Our empirical study on many real-world programs shows that Clever is highly efficient and accurate in clone detection and updating, and provides useful analysis of clone changes. : First of all, a developer could use Eclipse to work on a software project. At any time, (s)he can start code clone detection on any version of the project. When (s)he checks in the code, if clone detection has never been initiated, Clever will perform the detection. It reads source files and extracts important features. The initial detection is launched using our algorithm on those fragments (Section 5). In addition to the normal check-in data, clonerelated information is also stored for future updating.
Structure-oriented approaches in clone detection have become popular in both code-based and model... more Structure-oriented approaches in clone detection have become popular in both code-based and model-based clone detection. However, existing methods for capturing structural information in software artifacts are either too computationally expensive to be efficient or too light-weight to be accurate in clone detection. In this paper, we present Exas, an accurate and efficient structural characteristic feature extraction approach that better approximates and captures the structure within the fragments of artifacts. Exas structural features are the sequences of labels and numbers built from nodes, edges, and paths of various lengths of a graph-based representation. A fragment is characterized by a structural characteristic vector of the occurrence counts of those features. We have applied Exas in building two clone detection tools for source code and models. Our analytic study and empirical evaluation on open-source software show that Exas and its algorithm for computing the characteristic vectors are highly accurate and efficient in clone detection.
Page 1. Abstract The concept of a novel axial flux permanent magnet machine for flywheel energy ... more Page 1. Abstract The concept of a novel axial flux permanent magnet machine for flywheel energy storage system is presented. Modeling and control of this novel flywheel energy storage system are given. This flywheel energy ...
Magnetic data are presented that indicate the VO3 array of the perovskite CeVO3 exhibits the same... more Magnetic data are presented that indicate the VO3 array of the perovskite CeVO3 exhibits the same anomalous properties as in LaVO3, including (1) a first-order magnetostrictive distortion below a Tt < TN, (2) a canted-spin ferromagnetism below TN, (3) a reversal of the direction of the vanadium atomic moments on traversing Tt, and (4) suppression of Tt in an isostructural
Localized-itinerant electronic transition in the perovskite system La 1-x Ca x VO 3. Hoan C. Nguy... more Localized-itinerant electronic transition in the perovskite system La 1-x Ca x VO 3. Hoan C. Nguyen and John B. Goodenough Center for Materials Science and Engineering, ETC 9.102, The University of Texas at Austin, Austin, Texas 78712-1063. Received 28 March 1995 ...
Magnetic studies of some orthovanadates. Hoan C. Nguyen and John B. Goodenough Center for Materia... more Magnetic studies of some orthovanadates. Hoan C. Nguyen and John B. Goodenough Center for Materials Science and Engineering, ETC 9.102, The University of Texas at Austin, Austin, Texas 78712-1063. Received 22 December 1994 ...
Rheumatoid arthritis affects millions of people all over the world. Up to 86% of cases involve ce... more Rheumatoid arthritis affects millions of people all over the world. Up to 86% of cases involve cervical spine alterations. Cervical spine instability patterns related to rheumatoid arthritis are: atlanto-axial subluxation, basilar invagination and subaxial instability. Once neurological deficit develops, progression can be fast and even lead to death. Rheumatoid arthritis treatment is mainly nonsurgical. Current medication and treatment protocols may prevent or delay the development of atlanto-axial disease. Periodical clinical and radiological examination help diagnose patients who already have neurological symptoms or those who are at risk of developing them, and who should thus be considered for surgical treatment. Preoperative neurological deficit is a predictor of postoperative neurological recovery, thus the importance of early detection and referral of patients at risk. Surgical treatment should be performed in specialized centers, by multidisciplinary groups. Along with early intervention, this should help reduce perioperative complications.
Abstract Previous research confirms the existence of recurring bug fixes in software systems. Ana... more Abstract Previous research confirms the existence of recurring bug fixes in software systems. Analyzing such fixes manually, we found that a large percentage of them occurs in code peers, the classes/methods having the similar roles in the systems, such as providing similar functions and/or participating in similar object interactions. Based on graph-based representation of object usages, we have developed several techniques to identify code peers, recognize recurring bug fixes, and recommend changes for code units from the bug ...
The interplay of multiple objects in object-oriented programming often follows specific protocols... more The interplay of multiple objects in object-oriented programming often follows specific protocols, for example certain orders of method calls and/or control structure constraints among them that are parts of the intended object usages. Unfortunately, the information is not always documented. That creates long learning curve, and importantly, leads to subtle problems due to the misuse of objects.
Geological and hydrogeological processes controlling recharge and the mobilization of As were inv... more Geological and hydrogeological processes controlling recharge and the mobilization of As were investigated in a shallow Holocene aquifer on the Red River flood plain near Hanoi, Vietnam. The geology was investigated using surface resistivity methods, geophysical borehole logging, drilling of boreholes and installation of more than 200 piezometers. Recharge processes and surface-groundwater interaction were studied using (i) time-series of hydraulic head distribution in surface water and aquifers, (ii) the stable isotope composition of waters and (iii) numerical groundwater modeling. The Red River and two of its distributaries run through the field site and control the groundwater flow pattern. For most of the year, there is a regional groundwater flow towards the Red River. During the monsoon the Red River water stage rises up to 6 m and stalls the regional groundwater flow. The two distributaries recharge the aquifer from perched water tables in the dry season, whilst in the flooding period surface water enters the aquifer through highly permeable bank sediments. The result is a dynamic groundwater flow pattern with rapid fluctuations in the groundwater table. A transient numerical model of the groundwater flow yields an average recharge rate of 60-100 mm/a through the confining clay, and a total recharge of approximately 200 mm/a was estimated from 3 H/ 3 He dating of the shallow groundwater. Thus in the model area, recharge of surface water from the river distributaries and recharge through a confining clay is of the same magnitude, being on average around 100 mm/a. The thickness of the confining clay varies between 2 and 10 m, and affects the recharge rate and the transport of electron acceptors (O 2 , NO À 3 and SO 2À 4 ) into the aquifer. Where the clay layer is thin, an up to 2 m thick oxic zone develops in the shallow aquifer. In the oxic zone the As concentration is less than 1 lg/L but increases in the reduced zone below to 550 lg/ L. In the Holocene aquifer, As is mobilized at a rate of around 14 lg/L/a. An As mass balance for the field site shows that around 1100 kg of As is annually leached from the Holocene sand and discharged into the Red River, corresponding to 0.01% of the total pool of As now present in the Holocene sand.
Code clone management has been shown to have several benefits for software developers. When sourc... more Code clone management has been shown to have several benefits for software developers. When source code evolves, clone management requires a mechanism to efficiently and incrementally detect code clones in the new revision. This paper introduces an incremental clone detection tool, called ClemanX. Our tool represents code fragments as subtrees of Abstract Syntax Trees (ASTs), measures their similarity levels based on their characteristic vectors of structural features, and solves the task of incrementally detecting similar code as an incremental distance-based clustering problem. Our empirical evaluation on large-scale software projects shows the usefulness and good performance of ClemanX.
However, there has been little work on clone detection in models with the limitations on detectio... more However, there has been little work on clone detection in models with the limitations on detection precision and completeness. This paper presents ModelCD, a novel clone detection tool for Matlab/Simulink models, that is able to efficiently and accurately detect both exactly matched and approximate model clones. The core of ModelCD is two novel graph-based clone detection algorithms that are able to systematically and incrementally discover clones with a high degree of completeness, accuracy, and scalability. We have conducted an empirical evaluation with various experimental studies on many real-world systems to demonstrate the usefulness of our approach and to compare the performance of ModelCD with existing tools.
Recent research results have shown more benefits of the management of code clones, rather than de... more Recent research results have shown more benefits of the management of code clones, rather than detecting and removing them. However, existing management approaches for code clone group evolution are still ad hoc, unsatisfactory, and limited. In this paper, we introduce a novel method for comprehensive code clone group management in evolving software. The core of our method is Cleman, an algorithmic framework that allows for a systematic construction of efficient and accurate clone group management tools. Clone group management is rigorously formulated by a formal model, which provides the foundation for Cleman framework. We use Cleman framework to build a clone group management tool that is able to detect high-quality clone groups and efficiently manage them when the software evolves. We also conduct an empirical evaluation on real-world systems to show the flexibility of Cleman framework and the efficiency, completeness, and incremental updatability of our tool.
Reusing existing library components is essential for reducing the cost of software development an... more Reusing existing library components is essential for reducing the cost of software development and maintenance. When library components evolve to accommodate new feature requests, to fix bugs, or to meet new standards, the clients of software libraries often need to make corresponding changes to correctly use the updated libraries. Existing API usage adaptation techniques support simple adaptation such as replacing the target of calls to a deprecated API, however, cannot handle complex adaptations such as creating a new object to be passed to a different API method, or adding an exception handling logic that surrounds the updated API method calls.
Page 1. 3784 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 58, NO. 9, SEPTEMBER 2011 A Novel ... more Page 1. 3784 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 58, NO. 9, SEPTEMBER 2011 A Novel Axial Flux Permanent-Magnet Machine for Flywheel Energy Storage System: Design and Analysis Trong Duy ...
Recent research results show several benefits of the management of code clones. In this paper, we... more Recent research results show several benefits of the management of code clones. In this paper, we introduce Clever, a novel clone-aware software configuration management (SCM) system. In addition to traditional SCM functionality, Clever provides clone management support, including clone detection and update, clone change management, clone consistency validating, clone synchronizing, and clone merging. Clever represents source code and clones as (sub)trees in Abstract Syntax Trees (ASTs), measures code similarity based on structural characteristic vectors, and describes code changes as tree editing scripts. The key techniques of Clever include the algorithms to compute tree editing scripts; to detect and update code clones and their groups; and to analyze the changes of cloned code to validate their consistency and recommend the relevant synchronization. Our empirical study on many real-world programs shows that Clever is highly efficient and accurate in clone detection and updating, and provides useful analysis of clone changes. : First of all, a developer could use Eclipse to work on a software project. At any time, (s)he can start code clone detection on any version of the project. When (s)he checks in the code, if clone detection has never been initiated, Clever will perform the detection. It reads source files and extracts important features. The initial detection is launched using our algorithm on those fragments (Section 5). In addition to the normal check-in data, clonerelated information is also stored for future updating.
Structure-oriented approaches in clone detection have become popular in both code-based and model... more Structure-oriented approaches in clone detection have become popular in both code-based and model-based clone detection. However, existing methods for capturing structural information in software artifacts are either too computationally expensive to be efficient or too light-weight to be accurate in clone detection. In this paper, we present Exas, an accurate and efficient structural characteristic feature extraction approach that better approximates and captures the structure within the fragments of artifacts. Exas structural features are the sequences of labels and numbers built from nodes, edges, and paths of various lengths of a graph-based representation. A fragment is characterized by a structural characteristic vector of the occurrence counts of those features. We have applied Exas in building two clone detection tools for source code and models. Our analytic study and empirical evaluation on open-source software show that Exas and its algorithm for computing the characteristic vectors are highly accurate and efficient in clone detection.
Page 1. Abstract The concept of a novel axial flux permanent magnet machine for flywheel energy ... more Page 1. Abstract The concept of a novel axial flux permanent magnet machine for flywheel energy storage system is presented. Modeling and control of this novel flywheel energy storage system are given. This flywheel energy ...
Uploads
Papers by hoan nguyen