• Journal of Korea Multimedia Society
• /
• v.23 no.5
• /
• pp.641-649
• /
• 2020

As the usage of mobile devices extremely increases, malicious mobile apps(applications) that target mobile users are also increasing. It is challenging to detect these malicious apps using traditional malware detection techniques due to intelligence of today's attack mechanisms. Deep learning (DL) is an alternative technique of traditional signature and rule-based anomaly detection techniques and thus have actively been used in numerous recent studies on malware detection. In order to develop DL-based defense mechanisms against intelligent malicious apps, feeding recent datasets into DL models is important. In this paper, we develop a DL-based model for detecting intelligent malicious apps using KU-CISC 2018-Android, the most up-to-date dataset consisting of benign and malicious Android apps. This dataset has hardly been addressed in other studies so far. We extract OPcode sequences from the Android apps and preprocess the OPcode sequences using an N-gram model. We then feed the preprocessed data into LSTM and apply the concept of Information Gain to improve performance of detecting malicious apps. Furthermore, we evaluate our model with numerous scenarios in order to verify the model's design and performance.

• Journal of KIISE
• /
• v.41 no.10
• /
• pp.792-798
• /
• 2014

In spatial databases, R-tree is one of the most widely used indexing structures and many variants have been proposed for its performance improvement. Among these variants, Hilbert R-tree is a representative method using Hilbert curve to process large amounts of data without high cost split techniques to construct the R-tree. This Hilbert R-tree, however, is hardly applicable to large-scale applications in practice mainly due to high pre-processing costs and slow bulk-load time. To overcome the limitations of Hilbert R-tree, we propose a novel approach for parallelizing Hilbert mapping and thus accelerating bulk-loading of Hilbert R-tree on GPU memory. Hilbert R-tree based on GPU improves bulk-loading performance by applying the inversed-cell method and exploiting parallelism for packing the R-tree structure. Our experimental results show that the proposed scheme is up to 45 times faster compared to the traditional CPU-based bulk-loading schemes.

• Proceedings of the Korean Society for Cognitive Science Conference
• /
• 2005.05a
• /
• pp.151-153
• /
• 2005

We investigated the brain substrate of repetition priming on the implicit memory taskusing low-resolution electromagnetic tomography (LORETA) with high-density 128 channel EEG and individual MRI as a realistic head model. Thirteen right-handed, healthy subjects performed a word/nonword discrimination task, in which the words and nonwords were presented visually,and some of the words appeared twice with a lag of one or five items. All of the subjects exhibited repetition priming with respect to the behavioral data, in which a faster reaction time was observed to the repeated word (old word) than to the first presentation of the word (new word). The old words elicited more positive-going potentials than the new words, beginning at 200 ms and lasting until 500 ms post-stimulus. We conducted source reconstruction using LORETA at a latency of 400 ms with the peak mean global field potentials and used statistical parametric mapping for the statistical analysis. We found that the source elicited by the old words exhibited a statistically significant current density reduction in the left inferior frontal gyrus. This is the first study to investigate the generators of repetition priming using voxel-by-voxel statistical mapping of the current density with individual MRI and high-density EEG.

• The KIPS Transactions:PartA
• /
• v.10A no.6
• /
• pp.595-604
• /
• 2003

A Digital TV system is necessary for data Processing as well as video and audio processing. Especially in the case of interactive broadcasting, it should manage returning channel created by the Internet, PSTN, and so on. Because of many functionalities and multitasking jobs, it needs an Operating System. Embedded Linux as open source program can increase a cost effectiveness in market and has many advantages - reusable device drivers and application programs, more convenient developing environment using shell and file system, and easy problem resolution within Open Source Community. In this paper, we modified Embedded Linux kernel and cross developing environment for a big-endian system, redesigned devices for kernel execution, and configured system memory map in order to load a linux kernel. Also we developed an device driver for entire system control.

• The KIPS Transactions:PartA
• /
• v.14A no.7
• /
• pp.421-434
• /
• 2007

Among many other CG generated natural scenes, the representation of ocean surfaces is one of the most complicated and time-consuming problem because of its large extent and complex surface movement. We present a hybrid method to represent and animate unbound deep-water ocean surfaces by utilizing graphics processor as both simulation and rendering core. Our technique is mainly based on spectral approaches that generate a high-detailed height field using Fourier transform on a 2D regular grid. Additionally, we incorporate Gerstner model and generate low-detailed height field on a 2D projected grid in order to represent large waves and main structure of ocean surface. There is no interruption between CPU and GPU, and no need to transfer simulation results from the system memory to graphics hardware because the entire simulation and rending processes are done on graphics processor. As a result we can synthesize and render realistic water surfaces in real-time. Proposed techniques are readily adoptable to real-time applications such as computer games that have heavy work load on CPU but still demand plausible natural scenes.

• KIPS Transactions on Software and Data Engineering
• /
• v.2 no.7
• /
• pp.471-478
• /
• 2013

This paper proposes a black-box based test case generation method for Simulink/Stateflow model utilizing the RRT algorithm which is a method to efficiently solve the path planning for complicated systems. The proposed method in the paper tries to solve the reachability problem with the RRT algorithm, which has to be solved for black-box based test case generations. A major problem of the RRT based test case generation algorithms is that the cost such as running time and required memory size is too much for complicated Stateflow model. The typical RRT algorithm expands rapidly-exploring random tree (RRT) in a single state space. But the proposed method expands it in dynamic state space based on the state of Simulink model, consequently reducing the cost. In the paper, a new definition of RRT state space, a distance measure and a test case generation algorithm are proposed. The performance of proposed method is verified through the experiment against Stateflow model.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.429-438
• /
• 1994

Three-dimensional analyses of multistory structures with wings using finite element models require tedious input data preparation, longer computation time. and larger computer memory. So this study lays emphasis on the development of efficient analysis models for a three-dimensional multistory structure with wings, including in-plane deformation of floor slabs. Since a three-dimensional multistory structure with wings is regarded as a combination of wing structures and their junction in this study, the proposed analysis models are easily applicable to multistory structures with plans in the shape of letters Y, U, H, etc. Dynamic analyses results obtained using proposed models are in excellent agreement to those acquired using three-dimensional finite element models in terms of natural vibration periods, mode shapes and displacement time history.

• The Journal of the Korea Contents Association
• /
• v.17 no.3
• /
• pp.370-381
• /
• 2017

Recently, a complex event processing system has been introduced to quickly and efficiently process real-time events in various applications. Since the existing complex event processing schemes do not consider the similarity and duplication of operators, they perform a lot of computations and consume memory. To solve such problems, this paper proposes an efficient complex event processing scheme considering similar operators and duplication operations. When the same primitive events have similar operations, the proposed scheme combines them into one virtual operator. For duplicated operations, the proposed scheme processes only one of them first, and then processes the others using the results of the already processed operation when the same operation is subsequently performed. It is shown through performance comparison that the proposed scheme outperforms the existing scheme in terms of the whole operation throughput.

• Korean Institute of Interior Design Journal
• /
• v.21 no.2
• /
• pp.112-122
• /
• 2012

The purpose of this study is to provide fundamental data that can improve added value of commercial space strategically using the identification of relationship between the process of consumers' purchasing psychology (AIDMA : Attention, Interest, Desire, Memory, Action) and elements of interior design. For this purpose, case study and survey were carried out on food and beverage spaces, where they were doing business for more than two years, were selected from the ones appeared in the interior journal "A." Based on the study, basic details including a ground plan, design summary and representative image were identified through preliminary research, and a researcher visited the target spaces and carried out a research and analysis on interior design elements. Three spaces among targets of the case study were selected to identify the relation between design elements and AIDMA items which consumers feel, and the survey was conducted on the customers of the selected food and beverage spaces. Results of the case study on the 18 food and beverage spaces showed that features of the each of AIDMA items in material and color elements were most well expressed. As a result of survey conducted on visitors of each food and beverage space, features of each item were expressed in overall design elements. In particular, space elements and color elements in "Space 1," space elements and lighting elements in "Space 2" and space elements, furniture & objet elements in "Space 3" were most well expressed in each space. There were slight differences depending on individual characteristics such as design concept, location and business operation of target food and beverage spaces but attributes of AIDMA items were remarkably recognized in common in the space elements.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.30 no.4
• /
• pp.335-342
• /
• 2012

3D point cloud is widely used in Architecture, Civil Engineering, Medical, Computer Graphics, and many other fields. Due to the improvement of 3D laser scanner, a massive 3D point cloud whose gigantic file size is bigger than computer's memory requires efficient preprocessing and visualization. We suggest a data structure to solve the problem; a 3D point cloud is gradually subdivided by arbitrary-sized cube grids structure and corresponding point cloud subsets generated by the center of each grid cell are achieved while preprocessing. A massive 3D point cloud file is tested through two algorithms: QSplat and ours. Our algorithm, grid-based, showed slower speed in preprocessing but performed faster rendering speed comparing to QSplat. Also our algorithm is further designed to editing or segmentation using the original coordinates of 3D point cloud.