• 융합신호처리학회논문지
• /
• 제2권1호
• /
• pp.53-62
• /
• 2001

조명 및 반사광의 성질에 의해 블러링이 발생하고 이런 영상을 인식하는 경우 정확한 에지 검출이 어렵게 된다. 본 논문에서는 블러링된 영상에서 에지를 최적으로 검출하기 위해 일정하게 에지를 검출할 수 있는 가우시안 함수와 2차 미분 함수를 합성한 새로운 하이브리드 함수를 제안하고 실제 영상과 컨볼루션 한 후 함수의 local scale 계수 $\sigma$ 값을 변화시키면서, Canny 알고리즘의 방향성 에지 검출방법을 적용하여 에지를 검출하였다. 그 결과 Sobel, Robert, Canny 에지 검출방법보다 0.2~14㏈ 정도의 에지 검출특성이 개선됨을 확인하였다.

• Structural Monitoring and Maintenance
• /
• 제9권2호
• /
• pp.179-200
• /
• 2022

This paper proposes a data-driven methodology for online early damage identification under changing environmental conditions. The proposed method relies on two data analysis methods: feature-based method and hybrid principal component analysis (PCA) and kernel PCA to separate damage from environmental influences. First, spectral sub-band features, namely, spectral sub-band centroids (SSCs) and log spectral sub-band energies (LSSEs), are proposed as damage-sensitive features to extract damage information from measured structural responses. Second, hybrid modeling by integrating PCA and kernel PCA is performed on the spectral sub-band feature matrix for data normalization to extract both linear and nonlinear features for nonlinear procedure monitoring. After feature normalization, suppressing environmental effects, the control charts (Hotelling T² and SPE statistics) is implemented to novelty detection and distinguish damage in structures. The hybrid PCA-KPCA technique is compared to KPCA by applying support vector machine (SVM) to evaluate the effectiveness of its performance in detecting damage. The proposed method is verified through numerical and full-scale studies (a Bridge Health Monitoring (BHM) Benchmark Problem and a cable-stayed bridge in China). The results demonstrate that the proposed method can detect the structural damage accurately and reduce false alarms by suppressing the effects and interference of environmental variations.

• International Journal of Computer Science & Network Security
• /
• 제23권7호
• /
• pp.186-192
• /
• 2023

Malwares are becoming a major problem nowadays all around the world in android operating systems. The malware is a piece of software developed for harming or exploiting certain other hardware as well as software. The term Malware is also known as malicious software which is utilized to define Trojans, viruses, as well as other kinds of spyware. There have been developed many kinds of techniques for protecting the android operating systems from malware during the last decade. However, the existing techniques have numerous drawbacks such as accuracy to detect the type of malware in real-time in a quick manner for protecting the android operating systems. In this article, the authors developed a hybrid model for android malware detection using a decision tree and KNN (k-nearest neighbours) technique. First, Dalvik opcode, as well as real opcode, was pulled out by using the reverse procedure of the android software. Secondly, eigenvectors of sampling were produced by utilizing the n-gram model. Our suggested hybrid model efficiently combines KNN along with the decision tree for effective detection of the android malware in real-time. The outcome of the proposed scheme illustrates that the proposed hybrid model is better in terms of the accurate detection of any kind of malware from the Android operating system in a fast and accurate manner. In this experiment, 815 sample size was selected for the normal samples and the 3268-sample size was selected for the malicious samples. Our proposed hybrid model provides pragmatic values of the parameters namely precision, ACC along with the Recall, and F1 such as 0.93, 0.98, 0.96, and 0.99 along with 0.94, 0.99, 0.93, and 0.99 respectively. In the future, there are vital possibilities to carry out more research in this field to develop new methods for Android malware detection.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.159-160
• /
• 2008

Initial Ranging Detection and Synchronization is suggested for IEEE 802.16e OFDMA Systems. However ranging is vulnerable to the channel selectivity and other user's interference at low SNR. This paper presents enhanced ranging scheme that improves ranging detection process using the combine multiple FFT blocks and cope with channel selectivity and other user's interference at low SNR. Based on the ranging detection timing offset is calculated for synchronization.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2019년도 전력전자학술대회
• /
• pp.77-79
• /
• 2019

Islanding detection is one of the most important issues for the distributed generation (DG) systems connected to the power grid. The conventional passive islanding detection methods inherently have a non-detection zone (NDZ), and active islanding detection methods may deteriorate the power quality of a power system. This paper proposes a novel hybrid islanding detection method based on Digital Lock-In Amplifier with no NDZ by monitoring the harmonics present in the grid. Proposed method detects islanding by passively monitoring the grid voltage harmonics and verify it by injecting small perturbation for only three-line cycles. Unlike FFT for the harmonic extraction, DLA HC have lower computational burden, moreover, DLA can monitor harmonic in real time, whereas, FFT has certain propagation delay. The simulation results are presented to highlight the effectiveness of the proposed technique. In order to prove the performance of the proposed method it is compared with several passive islanding detection methods. The experimental results confirm that the proposed method exhibits outstanding performance as compared to the conventional methods.

• 한국멀티미디어학회논문지
• /
• 제24권1호
• /
• pp.106-116
• /
• 2021

To increase the quality of the system in the subjective-type question grading and document classification, we need the paragraph detection. But it is not easy because it is accompanied by semantic analysis. Many researches on the paragraph detection solve the detection problem using the word based clustering method. However, the word based method can not use the order and dependency relation between words. This paper suggests the paragraph detection system using syntactic-semantic relation between words with the Korean syntactic-semantic analysis. This system is the hybrid system of word based, concept based, and syntactic-semantic tree based detection. The experiment result of the system shows it has the better result than the word based system. This system will be utilized in Korean subjective question grading and document classification.

• 센서학회지
• /
• 제14권3호
• /
• pp.198-205
• /
• 2005

Recently, the systems using multiple sensors such as magnetic, acoustic and pressure sensor are used for detection of underwater objects or vehicles. Those systems have difficulty of maintenance and repair because they operate underwater. Thus, this paper describes a hybrid detection system with long term operating reliability. This has a multi-signal transmission structure to have a high reliability. First, a signal transmission & receiving part, which transfers data from underwater sensors to land and receive control message from land through optical cable, has 4 multi-path. Second, the nodes for signal transmission are connected dually each other with single-hop construction and sensors are connected to a couple of neighboring nodes. This enables the output signal to transmit from a node to the next node and the next but one node together. Also, the signal from a sensor can be transmitted to two nodes at the same time. Therefore, the system with this construction has high reliability in long term operation because it makes possible to transmit sensor data to another node which works normally although a transmission node or cable in system have some faults.

• Journal of Advanced Marine Engineering and Technology
• /
• 제20권1호
• /
• pp.31-36
• /
• 1996

In recent years, as the electonic industry has become more advanced, the LPM(Linear Pulse Motor) has appeared in a wide range of applications because of easier control, operation by open-loop control, high positioning accuracy, and retrieval of position or velocity data by the input pulses. In this study, we deal with the development of a position detection device attached to a hybrid LPM in our laboratory. Precise position detection signals could be sensed by the synchronous rectifier method from the LPM stator scale. In addition, we can keep the amplitude constant by using an AGC(Automatic Gain Control) circuit. Experimental results show that the position data is good enough to perform the LPM position control.

• 대한의생명과학회지
• /
• 제11권1호
• /
• pp.51-56
• /
• 2005

The detection of high-risk human papilloma virus (HPV) allows us to predict the presence and future development of cervical intraepitheliallesion. In this study, we compared Hybrid Capture II and DNA chip methods for detection of HPV in cervical swab samples. And we evaluated the clinical efficacy and diagnostic performance of HPV DNA chip and Hybrid Capture II for detecting HPV in cervical neoplastic lesions. Seventy four patients were classified into three groups according to their histologic diagnosis: Group I (nonspecific chronic cervicitis), Group II (low-grade squamous intraepithelial lesion (SIL); koilocytosis, and mild dysplasia), and Group III (high-grade SIL;, moderate, severe dysplasia and in situ carcinoma). Cytologic diagnosis were based on the Bethesda System. Hybrid Capture II and DNA chip methods were performed to detect HPV. In 41 of the 74 cervical samples $(55.4\%)$, HPV DNAs were detected by Hybrid Capture II. In Group III, HPV-positive cases were detected in 15 $(20.3\%)$ of 74 patients by Hybrid Capture II. 25 patients with ASCUS cytology were histopathologically examined: 9 cases $(36\%)$ were Group II. In 18 patients with low-grade SIL cytology, 13 cases $(72.2\%)$ were Group II and 3 cases $(16.7\%)$ were Group III. 12 cases $(92.3\%)$ were Group ill of 13 patients with high-grade SIL cytology. The sensitivity of each test was $82\%$ in Hybrid Capture II and $53.9\%$ in DNA chip test. And the specificity was $74.3\%,\;85.7\%$ in Hybrid Capture II and DNA chip. In conclusion, Hybrid Capture II test is more sensitive than DNA chip in detecting women with cervical neoplastic lesions. Especially, in diagnosing of ASCUS, Hybrid Capture II test is more sensitive. Therefore, Hybrid Capture II test for cancer-associated HPV DNA is a viable option in the management of women with ASCUS.

• 전력전자학회논문지
• /
• 제19권4호
• /
• pp.312-319
• /
• 2014

When distributed generation such as a wind power system is connected to the grid, it should meet grid requirements like IEEE Std. 1547, which regulates the anti-islanding method. Since the islanding may cause damage on electrical equipments or safety hazards for utility line worker, a distributed generation should detect it as soon as possible. This paper proposes a hybrid anti-islanding method coupled with the active and passive detection methods. To enhance the harmonic extraction capability for an active harmonic injection method, cascaded second-order band-pass filter and signal processing scheme are employed. Simulation and experiments are carried out under the islanding test condition specified in IEEE Std. 1547. Passive over/under voltage and over/under frequency methods are combined with the active method to improve the detection speed under certain condition. The simulation and experimental results are presented to verify that the proposed hybrid anti-islanding method can effectively detect the islanding.