• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1866-1883
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• 2019

As the youngest branch of information hiding, network covert timing channels conceal the existence of secret messages by manipulating the timing information of the overt traffic. The popular model-based framework for constructing covert timing channels always utilizes cumulative distribution function (CDF) of the inter-packet delays (IPDs) to modulate secret messages, whereas discards high-order statistics of the IPDs completely. The consequence is the vulnerability to high-order statistical tests, e.g., entropy test. In this study, a rich security model of covert timing channels is established based on IPD chains, which can be used to measure the distortion of multi-order timing statistics of a covert timing channel. To achieve rich security, we propose two types of covert timing channels based on nested lattices. The CDF of the IPDs is used to construct dot-lattice and interval-lattice for quantization, which can ensure the cell density of the lattice consistent with the joint distribution of the IPDs. Furthermore, compensative quantization and guard band strategy are employed to eliminate the regularity and enhance the robustness, respectively. Experimental results on real traffic show that the proposed schemes are rich-secure, and robust to channel interference, whereas some state-of-the-art covert timing channels cannot evade detection under the rich security model.

• 한국멀티미디어학회논문지
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• 제10권12호
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• pp.1752-1761
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• 2007

Location-based services are a recent concept that integrates a mobile device's location with other information in order to provide added value to a user. Although Location-based Services provide users with comfortable information, it is a complex task to manage and share heterogeneous and numerous data in decentralized environments. In this paper, we propose the Semantic LBS Model as one of the solution to resolve the problem. The Semantic LBS Model is a LBS middleware model that includes an ontology-based data model for LBS POI information and its processing mechanism based on Semantic Web technologies. Our model enables POI information to be described and retrieved over various domain-specific ontologies based on our proposed POIDL ontology. This mechanism provide rich expressiveness, interoperability, flexibility in describing and using information about POls, and it can enhance POI retrieval services.

• International Journal of Computer Science & Network Security
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• 제22권7호
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• pp.301-307
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• 2022

Energy consumption has grown alongside dramatic population increases. Statistics show that buildings in particular utilize a significant amount of energy, worldwide. Because of this, building energy prediction is crucial to best optimize utilities' energy plans and also create a predictive model for consumers. To improve energy prediction performance, this paper proposes a ResNet-LSTM model that combines residual networks (ResNets) and long short-term memory (LSTM) for energy consumption prediction. ResNets are utilized to extract complex and rich features, while LSTM has the ability to learn temporal correlation; the dense layer is used as a regression to forecast energy consumption. To make our model more robust, we employed Huber loss during the optimization process. Huber loss obtains high efficiency by handling minor errors quadratically. It also takes the absolute error for large errors to increase robustness. This makes our model less sensitive to outlier data. Our proposed system was trained on historical data to forecast energy consumption for different time series. To evaluate our proposed model, we compared our model's performance with several popular machine learning and deep learning methods such as linear regression, neural networks, decision tree, and convolutional neural networks, etc. The results show that our proposed model predicted energy consumption most accurately.

• International Journal of Computer Science & Network Security
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• 제22권5호
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• pp.317-319
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• 2022

Rich morphology language such as Arabic needs more investigation and method to improve the sentiment analysis task. Using all document parts in the process of the sentiment analysis may add some unnecessary information to the classifier. Therefore, this paper shows the ongoing work to use sentence location as a feature with Arabic sentiment analysis. Our proposed method employs a supervised sentiment classification method by enriching the feature space model with some information from the document. The experiments and evaluations that were conducted in this work show that our proposed feature in the sentiment analysis for Arabic improves the performance of the classifier compared to the baseline model.

• 대한지리학회지
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• 제43권2호
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• pp.220-234
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• 2008

안전과 보안이 현대사회의 중요한 관심사로 등장하고 있고 그 대상 영역이 실내 공간으로 넘어서 도시로 확대되고 있다. 도심지역에 수 많은 감시 센서들이 설치 운영되고 있다. 많은 보안 모니터링 맥락에서 감시 센서/네트워크의 수행능력 혹은 효율성은 조명의 변화와 같은 환경 조건에 제약을 받는다. 서로 보완적인 상이한 유형의 센서를 설치함으로써 개별 유형의 센서의 고장 혹은 한계를 극복할 수 있다는 것은 익히 잘 알려진 사실이다. 입지 분석과 모델링의 관점에서 관심사는 어떻게 보완적인 상이한 유형의 센서들의 적절한 입지를 결정하여 보안기능을 강화할 수 있느냐 이다. 이 연구는 k 개의 상이한 유형의 감시 센서의 위치를 결정하는 커버리지 기반의 최적화 모델을 제시한다. 이 모델은 상이한 유형의 센서 사이의 공통 커버리지와 동일 유형의 센서 사이의 중복 커버지리를 동시에 고려한다. 개발된 모델은 도심 지역에 센서를 위치시키는데 적용된다. 연구 결과는 공통 및 중복 커버리지가 동시에 모델링 될 수 있으며, 두 유형의 커버지리 사이의 tradeoff를 보여주는 많은 해들이 있음을 보여준다.

• International Journal of Computer Science & Network Security
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• 제23권2호
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• pp.13-30
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• 2023

Since the COVID-19 vaccine became available, people have been sharing their opinions on social media about getting vaccinated, causing discussions of the vaccine to trend on Twitter alongside certain events, making the website a rich data source. This paper explores people's perceptions regarding the COVID-19 vaccine during certain events and how these events influenced public opinion about the vaccine. The data consisted of tweets sent during seven important events that were gathered within 14 days of the first announcement of each event. These data represent people's reactions to these events without including irrelevant tweets. The study targeted tweets sent in Arabic from users located in Saudi Arabia. The data were classified as positive, negative, or neutral in tone. Four classifiers were used-support vector machine (SVM), naïve Bayes (NB), logistic regression (LOGR), and random forest (RF)-in addition to a deep learning model using BiLSTM. The results showed that the SVM achieved the highest accuracy, at 91%. Overall perceptions about the COVID-19 vaccine were 54% negative, 36% neutral, and 10% positive.

• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.202-206
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• 2023

Today, social media has become a vital tool. The world communicates and reaches the news and each other's opinions through social media accounts. Recently, considerable research has been done on analyzing social media due to its rich data content. At the same time, since the beginning of the COVID-19 pandemic, which has afflicted so many around the world, the search for a vaccine has been intense. There have been many studies analyzing people's feelings during a crisis. This study aims to understand people's opinions about available Coronavirus vaccines through a learning model that was developed for this purpose. The dataset was collected using Twitter's streaming Application Programming Interface (API) , then combined with another dataset that had already been collected. The final dataset was cleaned, then analyzed using Python. Polarity and subjectivity functions were used to obtain the results. The results showed that most people had positive opinions toward vaccines in general and toward the Pfizer one. Our study should help governments and decision-makers dispel people's fears and discover new symptoms linked to those listed by the World Health Organization.

• 정보보호학회논문지
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• 제15권6호
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• pp.27-35
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• 2005

현재의 네트워크 환경에서는 사용자들이 인터넷상의 여러 서버에 대하여 각각의 독립된 ID(Identity)를 사용하고 있기 때문에 사용자들이 많은 수의 ID와 패스워드를 관리해야하는 불편함이 있다. 이러한 문제를 해결하기 위해 ID 관리 시스템을 사용하지만, 앞으로 도래할 유비쿼터스 컴퓨팅 환경에서는 유무선 네트워크상의 수많은 컴퓨터들이 유기적으로 연결되기 때문에 사용자 ID 및 패스워드 관리가 더욱 복잡해지고, 기존의 단일 신뢰영역(COT: Circle of Trust)의 ID 관리 시스템으로는 이러한 어려움을 해결하기에 충분하지 않다. 본 논문에서는 이러한 문제를 해결하기 위해, 다중 신뢰영역 간의 federated ID 연동을 유선 컴퓨팅 환경에서뿐만 아니라 모바일 컴퓨팅 환경으로 확장하기 위한 federated ID 연동 모델을 제안하고 평가하였다.

• International Journal of Computer Science & Network Security
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• 제22권4호
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• pp.193-202
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• 2022

The classification of hyperspectral imagery (HSI) is essential in the surface of earth observation. Due to the continuous large number of bands, HSI data provide rich information about the object of study; however, it suffers from the curse of dimensionality. Dimensionality reduction is an essential aspect of Machine learning classification. The algorithms based on feature extraction can overcome the data dimensionality issue, thereby allowing the classifiers to utilize comprehensive models to reduce computational costs. This paper assesses and compares two HSI classification techniques. The first is based on the Joint Spatial-Spectral Stacked Autoencoder (JSSSA) method, the second is based on a shallow Artificial Neural Network (SNN), and the third is used the SVM model. The performance of the JSSSA technique is better than the SNN classification technique based on the overall accuracy and Kappa coefficient values. We observed that the JSSSA based method surpasses the SNN technique with an overall accuracy of 96.13% and Kappa coefficient value of 0.95. SNN also achieved a good accuracy of 92.40% and a Kappa coefficient value of 0.90, and SVM achieved an accuracy of 82.87%. The current study suggests that both JSSSA and SNN based techniques prove to be efficient methods for hyperspectral classification of snow features. This work classified the labeled/ground-truth datasets of snow in multiple classes. The labeled/ground-truth data can be valuable for applying deep neural networks such as CNN, hybrid CNN, RNN for glaciology, and snow-related hazard applications.

• 한국사회정책
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• 제25권3호
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• pp.3-35
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• 2018

이 글은 기본소득의 재정적 실현가능성과 기존 사회보장제도의 대안으로서의 효용을 부정하는 양재진(2018) 등의 주장을 비판적으로 검토하고, 효과적이고 효율적인 기본소득안 설계를 위한 몇 가지 제안을 하고자 한다. 재정적 실현가능성에 대해서는 역진적인 조세지출의 기본소득으로의 전환을 통해 세율 인상 없이도 상당한 규모의 기본소득 도입이 가능하며, 이는 상위층을 제외한 대다수에게 실질적인 감세 내지 현금지원 효과를 냄을 강조한다. 또한 기본소득의 과세소득화와 기존 현금급여 수급자와 수급액의 축소로 재정절감이 가능함을 주장한다. 소득재분배의 효과 면에서 기존 사회보장제도의 선별 능력이 좋지 않으며, 보편적인 복지가 선별적인 복지보다 재분배 효과에서 우월하다는 "재분배의 역설"이 기본소득에도 적용될 수 있음을 주장한다. 또, 재정중립적인 기본소득안의 재분배효과를 가상의 시나리오를 통해 보여준 후 국내외의 관련 연구들을 검토하여 기본소득이 사회보험이나 공적서비스 확대 이상으로 재분배효과를 나타내며 추가적인 여러 장점이 있음을 주장한다. 끝으로 이러한 연구들을 위한 인프라로서 가구조사 자료와 행정자료를 통합하고 각종 조세와 복지지출 관련 규정들을 수식화하여 결합한 제대로 된 조세-급여 모델 구축의 필요성을 강조한다.