Byung-Hyun Ha

Three-dimensional analysis of maxillary first molar mesiobuccal root canal configuration and curvature using micro-computed tomography.

OBJECTIVE The complex anatomic configuration of the maxillary first molar mesiobuccal (MB) root canal system has been the subject of several studies. The purpose of this investigation was to analyze the 3-dimensional (3D) characteristics of the maxillary first molar MB canal system using micro-computed tomography (microCT). STUDY DESIGN Extracted maxillary first molars (46) were scanned by microCT and their canals reconstructed by 3D modeling software. RESULTS In these MB roots, nearly two-thirds (65.2%) had 2 canals, fewer than one-third (28.3%) had only 1 canal, and a few (6.5%) had 3 canals. The most common root canal configuration was 2 distinct canals (type III: 37.0%), followed by 1 single canal (type I: 28.3%), 2 canals that joined together (type II: 17.4%), 1 canal that split into 2 (type IV: 10.9%), and 3 canals (type V: 6.5%). CONCLUSION MicroCT provided an in-depth analysis of canal configurations, as well as length, curvature, and location of calcified segments.

Comparison of Alternative Image Reformatting Techniques in Micro–Computed Tomography and Tooth Clearing for Detailed Canal Morphology

INTRODUCTION Micro-computed tomography (MCT) shows detailed root canal morphology that is not seen with traditional tooth clearing. However, alternative image reformatting techniques in MCT involving 2-dimensional (2D) minimum intensity projection (MinIP) and 3-dimensional (3D) volume-rendering reconstruction have not been directly compared with clearing. The aim was to compare alternative image reformatting techniques in MCT with tooth clearing on the mesiobuccal (MB) root of maxillary first molars. METHODS Eighteen maxillary first molar MB roots were scanned, and 2D MinIP and 3D volume-rendered images were reconstructed. Subsequently, the same MB roots were processed by traditional tooth clearing. Images from 2D, 3D, 2D + 3D, and clearing techniques were assessed by 4 endodontists to classify canal configuration and to identify fine anatomic structures such as accessory canals, intercanal communications, and loops. RESULTS All image reformatting techniques in MCT showed detailed configurations and numerous fine structures, such that none were classified as simple type I or II canals; several were classified as types III and IV according to Weine classification or types IV, V, and VI according to Vertucci; and most were nonclassifiable because of their complexity. The clearing images showed less detail, few fine structures, and numerous type I canals. Classification of canal configuration was in 100% intraobserver agreement for all 18 roots visualized by any of the image reformatting techniques in MCT but for only 4 roots (22.2%) classified according to Weine and 6 (33.3%) classified according to Vertucci, when using the clearing technique. CONCLUSIONS The combination of 2D MinIP and 3D volume-rendered images showed the most detailed canal morphology and fine anatomic structures.

A simulation model with a low level of detail for container terminals and its applications

As trade among countries grows, the performance of container terminals is becoming more important than ever. In this paper, we present a 3D real-time-visualization container- terminal simulation model based on Plant Simulation, a commercial simulation modeling and execution tool. Our model reproduces every detailed behavior of container-terminal equipment, including not only movements of yard tractors and cranes but also those of trolleys, spreaders, and other machinery. Such low-level representation enables our simulation model to be easily visualized in 3D form and to offer real-time interactive capability. We analyzed the performance of container terminals by varying the settings such as the speeds of trolleys and spreaders, in detail. The simulation model in this study is expected to be useful for assessment of the effects of prospective new equipment on the performance of container terminals and, thereby, for decision-making on the implementation of such equipment.

Learning Bayesian Network from Event Logs Using Mutual Information Test

A Bayesian network can be considered to be a powerful tool for various analyses (e.g. inference analysis, sensitivity analysis, evidence propagation, etc.), however, it is first necessary to obtain the Bayesian network structure of a given dataset, and this, an NP hard problem, is not an easy task. Among the available scoring metrics, the present study employed Mutual Information Test (MIT) to construct a Bayesian network from the event logs of port logistics data covering six days of observations. Additionally, dynamic programming was used to shorten the combinatorial calculation of the metrics and, later, to minimize the computation time. To validate our method, we conducted a case study of port processes using actual event logs from an Asian port.

An approximate analysis of expected cycle time in business process execution

The accurate prediction of business process performance during its design phase can facilitate the assessment of existing processes and the generation of alternatives. In this paper, an approximation method to estimate the cycle time of a business process is introduced. First, we propose a process execution scheme, with which Business Process Management Systems (BPMS) can control the execution of processes. Second, an approximation method for analyzing its cycle time, based on queueing theory, is presented. We consider agents as queueing servers with multi-class customers and predict the response time of the agents. The cycle time of the whole process is calculated using the expected response time and process structure, taking into account parallel process execution. Finally, the results from the analytical approximation are validated against those of a simulation. This analysis can be used to obtain an optimal process execution plan.

An Algorithm for Resource-Unconstrained Earliness-Tardiness Problem with Partial Precedences

In this paper, we consider the minimization of the total weighted earliness-tardiness penalty of jobs, regarding the partial precedences between jobs. We present an optimal scheduling algorithm in O(n(n+m log m)) where n is the number of jobs and m is the number of partial precedences. In the algorithm, the optimal schedule is constructed iteratively by considering each group of contiguous jobs as a block that is represented by a tree.

Automatic extraction of conversation protocols from a choreography specification of ubiquitous web services

While web service technology is becoming a de facto standard for integration of business applications, it is also rapidly emerging as an effective means for achieving inter-operability among the devices in network centric ubiquitous systems. When such a web service enabled device engages in a conversation with a service provider, it becomes necessary to define an interaction logic required between them. For this purpose, one can use a choreography language to specify the rules of engagement between the device and the web service provider. This paper presents a framework for automatically synthesizing conversation protocols from a choreography description defined in WS-CDL. The proposed framework adopts WSCL as a conversation protocol language, and defines a set of rules that can be used to effectively transform a WS-CDL specification into WSCL documents for collaborating peers. It is expected that the work presented in this paper can enhance the interoperability between web service-based processes in ubiquitous systems through automating the process of extracting conversation protocols from a choreography definition.