Ontology-lexicon-based question answering over linked data

Jabalameli, Mehdi,Nematbakhsh, Mohammadali,Zaeri, Ahmad Electronics and Telecommunications Research Instit 2020 ETRI Journal Vol.42 No.2

Recently, Linked Open Data has become a large set of knowledge bases. Therefore, the need to query Linked Data using question answering (QA) techniques has attracted the attention of many researchers. A QA system translates natural language questions into structured queries, such as SPARQL queries, to be executed over Linked Data. The two main challenges in such systems are lexical and semantic gaps. A lexical gap refers to the difference between the vocabularies used in an input question and those used in the knowledge base. A semantic gap refers to the difference between expressed information needs and the representation of the knowledge base. In this paper, we present a novel method using an ontology lexicon and dependency parse trees to overcome lexical and semantic gaps. The proposed technique is evaluated on the QALD-5 benchmark and exhibits promising results.

Analysis of issues in gate recess etching in the InAlAs/InGaAs HEMT manufacturing process

Byoung-Gue Min,Jong-Min Lee,Hyung Sup Yoon,Woo-Jin Chang,Jong-Yul Park,Dong Min Kang,Sung-Jae Chang,Hyun-Wook Jung Electronics and Telecommunications Research Instit 2023 ETRI Journal Vol.45 No.1

We have developed an InAlAs/InGaAs metamorphic high electron mobility transistor device fabrication process where the gate length can be tuned within the range of 0.13㎛-0.16㎛ to suit the intended application. The core processes are a two-step electron-beam lithography process using a three-layer resist and gate recess etching process using citric acid. An electron-beam lithography process was developed to fabricate a T-shaped gate electrode with a fine gate foot and a relatively large gate head. This was realized through the use of three-layered resist and two-step electron beam exposure and development. Citric acid-based gate recess etching is a wet etching, so it is very important to secure etching uniformity and process reproducibility. The device layout was designed by considering the electrochemical reaction involved in recess etching, and a reproducible gate recess etching process was developed by finding optimized etching conditions. Using the developed gate electrode process technology, we were able to successfully manufacture various monolithic microwave integrated circuits, including low noise amplifiers that can be used in the 28 GHz to 94 GHz frequency range.

Disputes over the Intellectual Property Rights of Telecommunications Standardization

Park, Ki-Shik,Kim, Young-Tae,Sohn, Hong Electronics and Telecommunications Research Instit 1998 ETRI Journal Vol.20 No.1

Both telecommunications standardization activities and an intellectual property rights (IPRs) system are regarded as effective mechanisms for improving social benefits. Because of inherent conflicts that exist between the two, however, serious problems are generated in the international arena where the competition for technology development and markets is becoming increasingly fierce. In this paper, ways of harmonizing the relationship between the two are explored and explained. For this purpose, telecommunications standardization and IPRs protection mechanisms are described, and their positive and negative effects as well as their inter-relationship are also analyzed. In addition, IPR case studies related to international standardization are explained and analyzed. The Current status and problems of IPRs policy of major international standardization organizations are analyzed as well. Finally, based on the results of the analyses, viable policy recommendations and research strategies for more comprehensive study of the above problems are proposed.

Phase Noise Reduction of Microwave HEMT Oscillators Using a Dielectric Resonator Coupled by a High Impedance Inverter

Lee, Moon-Que,Ryu, Keun-Kwan,Yom, In-Bok Electronics and Telecommunications Research Instit 2001 ETRI Journal Vol.23 No.4

The phase noise reduction in a configuration of the HEMT oscillator with a dielectric resonator coupled by a quarter-wavelength impedance inverter is investigated. Two HEMT oscillators for a satellite payload system are manufactured in the same configuration except for the coupling configuration of the dielectric resonator (DR) in order to empirically demonstrate the phase noise reduction. Experimental result shows that a phase noise reduction by 14 dB can be enhanced by increasing the characteristic impedance of a coupling microstrip impedance inverter.

Joint routing, link capacity dimensioning, and switch port optimization for dynamic traffic in optical networks

Khan, Akhtar Nawaz,Khan, Zawar H.,Khattak, Khurram S.,Hafeez, Abdul Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.5

This paper considers a challenging problem: to simultaneously optimize the cost and the quality of service in opaque wavelength division multiplexing (WDM) networks. An optimization problem is proposed that takes the information including network topology, traffic between end nodes, and the target level of congestion at each link/ node in WDM networks. The outputs of this problem include routing, link channel capacities, and the optimum number of switch ports locally added/dropped at all switch nodes. The total network cost is reduced to maintain a minimum congestion level on all links, which provides an efficient trade-off solution for the network design problem. The optimal information is utilized for dynamic traffic in WDM networks, which is shown to achieve the desired performance with the guaranteed quality of service in different networks. It was found that for an average link blocking probability equal to 0.015, the proposed model achieves a net channel gain in terms of wavelength channels (𝛾_w) equal to 35.72 %, 39.09 %, and 36.93 % compared to shortest path first routing and 𝛾_w equal to 29.41 %, 37.35 %, and 27.47 % compared to alternate routing in three different networks.

GaAs on Si substrate with dislocation filter layers for wafer-scale integration

Kim, HoSung,Kim, Tae-Soo,An, Shinmo,Kim, Duk-Jun,Kim, Kap Joong,Ko, Young-Ho,Ahn, Joon Tae,Han, Won Seok Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.5

GaAs on Si grown via metalorganic chemical vapor deposition is demonstrated using various Si substrate thicknesses and three types of dislocation filter layers (DFLs). The bowing was used to measure wafer-scale characteristics. The surface morphology and electron channeling contrast imaging (ECCI) were used to analyze the material quality of GaAs films. Only 3-㎛ bowing was observed using the 725-㎛-thick Si substrate. The bowing shows similar levels among the samples with DFLs, indicating that the Si substrate thickness mostly determines the bowing. According to the surface morphology and ECCI results, the compressive strained indium gallium arsenide/GaAs DFLs show an atomically flat surface with a root mean square value of 1.288 nm and minimum threading dislocation density (TDD) value of 2.4×10⁷ cm^-2. For lattice-matched DFLs, the indium gallium phosphide/GaAs DFLs are more effective in reducing the TDD than aluminum gallium arsenide/GaAs DFLs. Finally, we found that the strained DFLs can block propagate TDD effectively. The strained DFLs on the 725-㎛-thick Si substrate can be used for the large-scale integration of GaAs on Si with less bowing and low TDD.

Power analysis attack resilient block cipher implementation based on 1-of-4 data encoding

Shanmugham, Shanthi Rekha,Paramasivam, Saravanan Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.4

Side-channel attacks pose an inevitable challenge to the implementation of cryptographic algorithms, and it is important to mitigate them. This work identifies a novel data encoding technique based on 1-of-4 codes to resist differential power analysis attacks, which is the most investigated category of side-channel attacks. The four code words of the 1-of-4 codes, namely (0001, 0010, 1000, and 0100), are split into two sets: set-0 and set-1. Using a select signal, the data processed in hardware is switched between the two encoding sets alternately such that the Hamming weight and Hamming distance are equalized. As a case study, the proposed technique is validated for the NIST standard AES-128 cipher. The proposed technique resists differential power analysis performed using statistical methods, namely correlation, mutual information, difference of means, and Welch's t-test based on the Hamming weight and distance models. The experimental results show that the proposed countermeasure has an area overhead of 2.3× with no performance degradation comparatively.

Evaluations of AI-based malicious PowerShell detection with feature optimizations

Song, Jihyeon,Kim, Jungtae,Choi, Sunoh,Kim, Jonghyun,Kim, Ikkyun Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.3

Cyberattacks are often difficult to identify with traditional signature-based detection, because attackers continually find ways to bypass the detection methods. Therefore, researchers have introduced artificial intelligence (AI) technology for cybersecurity analysis to detect malicious PowerShell scripts. In this paper, we propose a feature optimization technique for AI-based approaches to enhance the accuracy of malicious PowerShell script detection. We statically analyze the PowerShell script and preprocess it with a method based on the tokens and abstract syntax tree (AST) for feature selection. Here, tokens and AST represent the vocabulary and structure of the PowerShell script, respectively. Performance evaluations with optimized features yield detection rates of 98% in both machine learning (ML) and deep learning (DL) experiments. Among them, the ML model with the 3-gram of selected five tokens and the DL model with experiments based on the AST 3-gram deliver the best performance.

Supervised-learning-based algorithm for color image compression

Liu, Xue-Dong,Wang, Meng-Yue,Sa, Ji-Ming Electronics and Telecommunications Research Instit 2020 ETRI Journal Vol.42 No.2

A correlation exists between luminance samples and chrominance samples of a color image. It is beneficial to exploit such interchannel redundancy for color image compression. We propose an algorithm that predicts chrominance components Cb and Cr from the luminance component Y. The prediction model is trained by supervised learning with Laplacian-regularized least squares to minimize the total prediction error. Kernel principal component analysis mapping, which reduces computational complexity, is implemented on the same point set at both the encoder and decoder to ensure that predictions are identical at both the ends without signaling extra location information. In addition, chrominance subsampling and entropy coding for model parameters are adopted to further reduce the bit rate. Finally, luminance information and model parameters are stored for image reconstruction. Experimental results show the performance superiority of the proposed algorithm over its predecessor and JPEG, and even over JPEG-XR. The compensation version with the chrominance difference of the proposed algorithm performs close to and even better than JPEG2000 in some cases.

Adaptive block tree structure for video coding

Baek, Aram,Gwon, Daehyeok,Son, Sohee,Lee, Jinho,Kang, Jung-Won,Kim, Hui Yong,Choi, Haechul Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.2

The Joint Video Exploration Team (JVET) has studied future video coding (FVC) technologies with a potential compression capacity that significantly exceeds that of the high-efficiency video coding (HEVC) standard. The joint exploration test model (JEM), a common platform for the exploration of FVC technologies in the JVET, employs quadtree plus binary tree block partitioning, which enhances the flexibility of coding unit partitioning. Despite significant improvement in coding efficiency for chrominance achieved by separating luminance and chrominance tree structures in I slices, this approach has intrinsic drawbacks that result in the redundancy of block partitioning data. In this paper, an adaptive tree structure correlating luminance and chrominance of single and dual trees is presented. Our proposed method resulted in an average reduction of -0.24% in the Y Bjontegaard Delta rate relative to the intracoding of JEM 6.0 common test conditions.