• Journal of Biomedical Engineering Research
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• v.34 no.4
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• pp.182-188
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• 2013

This study aims to develop a practical algorithm which can detect freezing of gait(FOG) in patients with Parkinson's disease(PD). Eighteen PD patients($68.8{\pm}11.1yrs.$) participated in this study, and three($68.7{\pm}4.0yrs.$) of them showed FOG. We suggested two time-domain algorithms(with 1-axis or 3-axes acceleration signals) and compared them with the frequency-domain algorithm in the literature. We measured the acceleration of left foot with a 3-axis accelerometer inserted at the insole of a shoe. In the time-domain method, the root-mean-square(RMS) acceleration was calculated in a moving window of 4s and FOG was defined as the periods during which RMS accelerations located within FOG range. The parameters in each algorithm were optimized for each subject using the simulated annealing method. The sensitivity and specificity were same, i.e., $89{\pm}8%$ for the time-domain method with 1-axis acceleration and were $91{\pm}7%$ and $90{\pm}8%$ for the time-domain method with 3-axes acceleration, respectively. Both performances were better in the time-domain methods than in the frequency-domain method although the results were statistically insignificant. The amount of calculation in the time-domain method was much smaller than in the frequency-domain method. Therefore it is expected that the suggested time domain algorithm would be advantageous in the systematic implementation of FOG detection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.3
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• pp.916-937
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• 2023

Most of the existing Distributed Denial-of-Service mitigation schemes in Software-Defined Networking are only implemented in the network domain managed by a single controller. In fact, the zombies for attackers to launch large-scale DDoS attacks are actually not in the same network domain. Therefore, abnormal traffic of DDoS attack will affect multiple paths and network domains. A single defense method is difficult to deal with large-scale DDoS attacks. The cooperative defense of multiple domains becomes an important means to effectively solve cross-domain DDoS attacks. We propose an efficient multi-domain DDoS cooperative defense mechanism by integrating blockchain and SDN architecture. It includes attack traceability, inter-domain information sharing and attack mitigation. In order to reduce the length of the marking path and shorten the traceability time, we propose an AS-level packet traceability method called ASPM. We propose an information sharing method across multiple domains based on blockchain and smart contract. It effectively solves the impact of DDoS illegal traffic on multiple domains. According to the traceability results, we designed a DDoS attack mitigation method by replacing the ACL list with the IP address black/gray list. The experimental results show that our ASPM traceability method requires less data packets, high traceability precision and low overhead. And blockchain-based inter-domain sharing scheme has low cost, high scalability and high security. Attack mitigation measures can prevent illegal data flow in a timely and efficient manner.

• Information and Communications Magazine
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• v.22 no.12
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• pp.105-119
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• 2005

광대역 유선통신망과 무선통신망이 통합되고, 통신과 방송이 융합되는 BcN 환경에서는 서비스 품질(QoS)이 보장되는 다양한 종류의 멀티미디어 서비스가 제공될 수 있어야하며, 다수의 통신방사업자가 제공하는 BcN들 간에 QoS 보장형 차별화서비스 제공을 위한 inter-domain 트래픽 엔지니어링 기능이 제공되어야한다. 특히, BcN 구축 초기 단계에서는 각 통신망 사업자가 개별적으로 구축 및 운영하는 BcN의 NNI signaling과 망운용관리 기능에 많은 차이점이 존재할 것으로 예상되기 때문에, 이들을 효율적으로 연동시킬 수 있는 inter-domain networking 기능 구현방안이 상세히 연구되어야한다. 본 논문에서는 BcN 환경에서의 QoS 보장형 차별화서비스제공을 위한 inter-domain 네트워킹 기술에 대하여 각 영역별로 살펴보며, 상용 BcN간 연동에 적용될 수 있는 트래픽 엔지니어링 및 관련 구현 기술에 대하여 살펴본다. Inter-domain networking 기능 모델로는 유럽연합(EU)의 IP Premium 프로젝트의 일환으로 개발된 MESCAL (Management of End-to-End Quality of Service Across the Internet at Large)을 분석하며, 세부 기능 구현 방안으로 MPLS NNI signaling 기반의 제어정면 연동방안, Web service 구조와 XML 기반의 망운용관리 평면 연동기능 구현 방안에 대하며 살펴본다.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1280-1285
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• 2017

In this paper, we consider iterative soft-decision feedback equalizers (sDFE), a.k.a. turbo equalizers for single-carrier transmission. Turbo equalizer takes log-likelihood ratio (LLR) feedback from channel decoder and convert the LLR into symbol estimates and variances to be used for the LLR update at the sDFE. Specifically, we consider both time domain and frequency-domain sDFE and compare their performances. The results shows that frequency-domain sDFE performs better than time-domain one and also that considerable gain can be obtained especially when the channel has deep nulls.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.5
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• pp.1610-1629
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• 2021

Failures frequently occurred in manufacturing machines due to complex and changeable manufacturing environments, increasing the downtime and maintenance costs. This manuscript develops a novel deep learning-based method named Multi-Domain Convolutional Neural Network (MDCNN) to deal with this challenging task with vibration signals. The proposed MDCNN consists of time-domain, frequency-domain, and statistical-domain feature channels. The Time-domain channel is to model the hidden patterns of signals in the time domain. The frequency-domain channel uses Discrete Wavelet Transformation (DWT) to obtain the rich feature representations of signals in the frequency domain. The statistic-domain channel contains six statistical variables, which is to reflect the signals' macro statistical-domain features, respectively. Firstly, in the proposed MDCNN, time-domain and frequency-domain channels are processed by CNN individually with various filters. Secondly, the CNN extracted features from time, and frequency domains are merged as time-frequency features. Lastly, time-frequency domain features are fused with six statistical variables as the comprehensive features for identifying the fault. Thereby, the proposed method could make full use of those three domain-features for fault diagnosis while keeping high distinguishability due to CNN's utilization. The authors designed massive experiments with 10-folder cross-validation technology to validate the proposed method's effectiveness on the CWRU bearing data set. The experimental results are calculated by ten-time averaged accuracy. They have confirmed that the proposed MDCNN could intelligently, accurately, and timely detect the fault under the complex manufacturing environments, whose accuracy is nearly 100%.

• Bulletin of the Korean Mathematical Society
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• v.52 no.4
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• pp.1253-1268
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• 2015

It is well known that an integral domain D is a UFD if and only if every nonzero prime ideal of D contains a nonzero principal prime. This is the so-called Kaplansky's theorem. In this paper, we give this type of characterizations of a graded PvMD (resp., G-GCD domain, GCD domain, $B{\acute{e}}zout$ domain, valuation domain, Krull domain, ${\pi}$-domain).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.977-978
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• 2013

• Journal of Sasang Constitutional Medicine
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• v.19 no.3
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• pp.75-88
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• 2007

1. Objectives The purpose of this study was to objectively diagnose American male and female's production of two vowels /a, i/ by Sasang Constitution. 2. Methods It was analyzed the constitutional characteristics of the American adults voices with PSSC-2004. of 134 cases of vowels /a, i/ with a duration of $2.5{\sim}3$ seconds were inputted in PSSC-2004 and analyzed into 40 factors. 3. Results and Conclusions 1) APQ In the male group's production of vowel /a/, the Soyangin's APQ(l), APQ(3) and APQ(4) were significantly high compared with those of Taeumin and Soeumin. 2) Shimmer In the male group's production of vowel /a/, Soeumin's Octave1 Shimmer was significantly low compared with that of Taeumin and Soeumin. In the male group's production of vowel /i/, Soeumin's D-Shimmer was significantly low compared with that of Taeumin and Soeumin. In the female group's production of vowel /a/, the Soyangin's C-Shimmer was significantly high compared with that of Taeumin and Soeumin. 3) Octave In the male group's production of vowel /a/, the Soyangin's Octave3, Octave4, Octave5, Octave6 and Octave1 Ratio were significantly high compared with those of Taeumin and Soeumin. In the male group's production of vowels /a, i/, the Soyangin's Octave4 was significantly high compared with that of Taeumin and Soeumin. 4) Energy In the male group's production of vowel /a/, the Soyangin's Time Domain Total Sum /Time Domain Count, Freq Domain Total Sum /cnt(0), 0k-4k Total Sum, Dev., A(A#, C, E, D#, E, F#) tot E, and A(C,, D#, F#) Dev. were significantly high compared with those of Taeumin and Soeumin. In the male group's production of vowel /i/, the Soyangin's Time Domain Total Sum /Time Domain Count, Freq Domain Total Sum /cnt(0) and 0k-4k Total Sum, Dev. were significantly high compared with those of Taeumin and Soeumin. 5) Peak In the male group's production of vowels /a/ and /i/,, the Soyangin's Peak1 Ratio was significantly low compared with that of Taeumin and Soeumin. In the male group's production of vowels /a/ and /i/,, the Soyangin's Peak10 Ratio, Time Domain Peak Total/Total Energy Sum, Time Domain Peak Dev. and Total/Total Dev. Sum were significantly high compared with those of Taeumin and Soeumin. 6) It is necessary to expand the research of the acoustic analysis of American and Korean to other countries in the diagnosis of the Sasang Constitution by using the voice characteristics.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.209-217
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• 2005

In this paper, we propose hierarchical inter-domain load balanced QoS routing in a large scale of network. And a scheme of calculating resources' costs for precomputation schemes in hierarchical routing is proposed. and a scheme for selecting a path among multiple precomputed paths is proposed. We also propose a QoS routing scheme for transit and intra traffic in a large scale of domain-based network. For a domain in the network, the routing scheme first precomputes K multiple paths between all pairs of ingress and egress border routers while considering balancing of the expected load then selects paths with the probability of path selection. The routing scheme combines inter and intra domain routings seamlessly and uses the same cost calculation scheme.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.3
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• pp.3-15
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• 2007

In this paper, we propose a simple scheme which produces a new S-box from a given S-box. We use well-known conversion technique between the polynomial functions over a finite field $F_{2^n}$ and the boolean functions from $F_2^n$ to $F_2$. We have applied this scheme to Rijndael S-box and obtained 29 new S-boxes, whose linear complexities are improved. We investigate their cryptographic properties via transform domain analysis.