Sungil Ham

Metrics for Quantifying the Similarities and Differences between IFC Files

Recently, several papers reported problems in data exchange using industry foundation classes (IFC). However, most comparisons were made based on a visual check, a manual count, and observation of properties that were selectively chosen. This study proposes a set of metrics for quantifying the similarities and differences between IFC files. The proposed metrics include the similarity rate, the matching rate, the globally unique identifier (GUID) preservation rate, the missing rate, and the addition rate. A long-term goal of this study is to develop a set of metrics for quantifying the information exchange rate between two IFC files. Automated identification of modified information versus newly generated information is an unsolved challenge. The proposed metrics were used in analyzing 88 IFC files generated from different systems to demonstrate the potential use of the proposed metrics.

Query Performance of the IFC Model Server Using an Object-Relational Database Approach and a Traditional Relational Database Approach

Most previous industry foundation classes (IFCs) servers were developed based on relational databases (RDBs), and many studies reported performance problems. This study developed the object-relational IFC (OR-IFC) server using the object-relational database (ORDB) approach to improve query performance by simplifying the mapping process of the inheritance structure and the aggregation concepts. In addition to the OR-IFC server, a RDB-based IFC server was also developed using mapping rules on the same database-management system as that on which the OR-IFC server was implemented to compare the performance of the ORDB- and RDB-based systems. The performance of the OR-IFC server and the RDB-based IFC server was evaluated using the Benchmark of Universal or Complex Kwery Ynterfaces benchmark method, and two test-case models with different sizes were used. The benchmark results clearly showed the query- performance improvement of the suggested OR approach. The OR-IFC server far outperformed the RDB-based server in every query related to object-oriented features such as inheritance, collection-type data, and referencing. DOI: 10.1061/(ASCE)CP.1943-5487.0000256.

Ubi-Floor: Design and Pilot Implementation of an Interactive Floor System

Ubi-floor is designed as an interactive floor system which allows user to interact with a floor based smart environment. Concerning context aware floor system, previous researches typically dealt with simple ideas of using gate pattern recognition supported by piezoelectric sensing devices or personal identification mediated by body weight estimation that cannot fully support position dependent context-awareness not to mention interactive interfaces based on it. This paper describes the design and implementation of an interactive floor system that is capable of dealing with various context aware multimedia applications such as visual displays, floor based games, navigation through geographical maps and recording or playing video memo triggered by the menu selections through foot step tracking interface. In addition, this pilot system is recognized as a highly scalable modular prototype of an innovative digital floor system applicable to diversified ubiquitous environments. Furthermore, the system is likely to provide highly enhanced usability of a smart floor system largely affected by various applications that could be adopted. Our further study will include the integration of this ubi-floor platform with various applications in the domain of ubiquitous computing.

Time-Based Joining Method for Generating Phylogenetic Trees of Architectural Plans

AbstractA method has been developed for automatically generating a phylogenetic tree of architectural plans based on graph theory, according to the properties of the plans and the timing of their appearance. A phylogenetic tree of architectural plans is a branching diagram that shows transitions of the architectural plans by period. In previous studies, researchers analyzed structural similarities and differences between architectural plans by comparing one floor plan to another. Such manual classification processes sometimes result in inconsistent classifications and are inefficient, especially when a large number of plans are compared and analyzed. In this paper, a new algorithmic approach is proposed, termed the time-based joining (TBJ) method, for quantitatively evaluating structural similarities between architectural plans and creating a phylogenetic tree of the analyzed architectural plans. The validity and consistency of the TBJ method’s results were tested by generating a phylogenetic tree of 422 ...

Space-connector model for representing the geometric properties of connections between spaces

ABSTRACT This study suggests a new spatial network model, called the space-connector model, for improving the representation of relations between spaces. Previous models have proved incapable of expressing the differences in the geometric and visual relations between spaces, such as the type and size of openings, the length of corridors, or the transparency of walls. New notations for explicitly representing these differences are proposed. This study suggests a modified process and map for calculating isovist, pedestrian route, based on the space-connector model. The space-connector model was implemented in the ‘ASpace’ tool and its functionality has been validated through an integrated analysis of space syntax and spatial properties as well as isovist and pedestrian route analysis.

Exploratory Methodology for Acquiring Architectural Plans Based on Spatial Graph Similarity

In architectural planning, previous cases of similar spatial program provide important data for architectural design. Case-based reasoning (CBR) paradigm in the field of architectural design is closely related to the designing behavior of a planner who makes use of similar architectural designs and spatial programs in the past. In CBR, spatial graph can be constituted with most fundamental data, which can provide a method of searching spatial program by using visual graphs. This study developed a system for CBR that can analyze the similarity through graph comparison and search for buildings. This is an integrated system that is able to compare space similarity of different buildings and analyze their types, in addition to the analysis on a space within a single structure.