• Journal of Digital Convergence
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• v.18 no.9
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• pp.57-62
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• 2020

Smart home based on Internet of things (IoT) is rapidly emerging as an exciting research and industry field. However, security and privacy have been critical issues due to the open feature of wireless communication channel. As a step towards this direction, Shuai et al. proposed an anonymous authentication scheme for smart home environment using Elliptic curve cryptosystem. They provided formal proof and heuristic analysis and argued that their scheme is secure against various attacks including de-synchronization attack, mobile device loss attack and so on, and provides user anonymity and untraceability. However, this paper shows that Shuai et al.'s scheme does not provide user anonymity nor untraceability, which are very important features for the contemporary IoT network environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1431-1440
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• 2000

In order to support efficiently the multimedia applications, such as virtual classroom, video conferencing and tele-medical, the efficient multipoint-to-multipoint(MP-to-MP) connection management function is essential. Shared tree is reported as the most useful method for this purpose. In this paper we propose a new MP-to-MP connection setup & management scheme, called CIMA(Cell Interleaved Multiplexing on ATM) scheme,which is a VC merging method for MP-to-MP communication using shared tree. In the CIMA scheme,MRM cell delivers the cell merging information to the next node. The receiving node can identfy cells which arrived through a channel using the same VPI/VCI by the merging information in the MRM cell. Therefore the CIMA scheme can solve easily the Cell Interleaving Problem(CIP) that happens in VC merging. We analyzed the overhead of the proposed CIMA by mathematical analysis,and simulated the buffer usage of CIMA with OPNET. As the result of analysis,we found that the CIMA scheme has acceptable merging overhead and doesn't cause the buffer scare problem.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.146-155
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• 2022

The purpose of this study is to investigate the recyclability of Shenlong in China using SWOT. The main analysis results are as follows. First, provided that the company's current capacity utilization rate is seriously insufficient, reducing staff is one among the effective ways. Second, Shenlong should open a web store to cater to young people's online shopping behavior, and further expand the brand visibility using national mainstream media and online shopping platforms like Taobao and JingDong to market Dongfeng Peugeot and Dongfeng Citroen on the whole network. Third, under the premise of maintaining the present best-selling models, Shenlong should appropriately reduce the amount of models, adjust the assembly capacity ratio of every model and every displacement in real time per the newest market trends, increase the agility of auto companies' production, and timely meet the wants of domestic consumers. Fourth, dual-brand coordination and channel integration are very necessary, and also the profitability and profitability of dealers are going to be further improved, thereby increasing sales. Fifth, target building new energy leading products of Shenlong, strive to attain the forefront of the industry within the sales of recent energy vehicles within 5 years, and gradually expand new energy vehicle products from passenger vehicles to passenger vehicles and commercial vehicles. Finally, the marketing field of Shenlong Automobile should achieve "three major changes", that is, change from a goal-driven type to a demand-driven type, cancel the bundling of outlet invoicing goals and delivery incentive tiers; start from basic capabilities, and set pragmatic and challenging goals; focus Channels, to realize following the activation of outlets, and single store sales increase.

• Journal of the Korea Society of Computer and Information
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• v.28 no.12
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• pp.1-7
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• 2023

The advent of deep learning technologies has led to the development of various medical applications, making healthcare services more convenient and effective. Among these applications, heart rate estimation is considered a vital method for assessing an individual's health. Traditional methods, such as photoplethysmography through smart watches, have been widely used but are invasive and require additional hardware. Recent advancements allow for contactless heart rate estimation through facial image analysis, providing a more hygienic and convenient approach. In this paper, we propose a lightweight methodology capable of accurately estimating heart rate in mobile environments, using a specialized 2-channel network structure based on 2D convolution. Our method considers both subtle facial movements and color changes resulting from blood flow and muscle contractions. The approach comprises two major components: an Encoder for analyzing image features and a regression layer for evaluating Blood Volume Pulse. By incorporating both features simultaneously our methodology delivers more accurate results even in computing environments with limited resources. The proposed approach is expected to offer a more efficient way to monitor heart rate without invasive technology, particularly well-suited for mobile devices.

• Journal of the Korea Society for Simulation
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• v.20 no.4
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• pp.81-89
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• 2011

Underwater wireless network can be useful in various fields such as underwater environment observation, catastrophe prevention, ocean resources exploration, ocean organism research, and vessel sinking exploration. We need to develop an efficient design for Medium Access Control (MAC) protocol to improve multiple data communication in underwater environment. Aloha protocol is one of the basic and simple protocols, but it has disadvantage such as collision occurs oftenly in communication. If there is collision occured in RF communication, problem can be solved by re-sending the data, but using low frequency in underwater, the re-transmission has difficulties due to slow bit-rate. So, Time Division Multiple Access (TDMA) based MAC protocol is going to be used to avoid collisions, but if there is no data to send in existing TDMA, time slot should not be used. Therefore, this paper proposes dynamic TDMA protocol mechanism with reducing the time slots by sending short "I Have No Data" (IHND) message, if there is no data to transmit. Also, this paper presents mathematic analysis model in relation to data throughput, channel efficiency and verifies performance superiority by comparing the existing TDMA protocols.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.315-319
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• 1996

We have developed a prototype patient monitoring system including module-based bedside units, interbed network, and central stations. A bedside unit consists of a color monitor and a main CPU unit with peripherals including a module controller. It can also include up to 3 module cases and 21 different modules. In addition to the 3-channel recorder module, six different physiological parameters of ECG, respiration, invasive blood pressure, noninvasive blood pressure, body temperature, and arterial pulse oximetry with plethysmogaph are provided as parameter modules. Modules and a module controller communicate with up to 1Mbps data rate through an intrabed network based on RS-485 and HDLC protocol. Bedside units can display up to 12 channels of waveforms with any related numeric informations simultaneously. At the same time, it communicates with other bedside units and central stations through interbed network based on 10Mbps Ethernet and TCP/IP protocol. Software far bedside units and central stations fully utilizes gaphical user interface techniques and all functions are controlled by a rotate/push button on bedside unit and a mouse on central station. The entire system satisfies the requirements of AAMI and ANSI standards in terms of electrical safety and performances. In order to accommodate more advanced data management capabilities such as 24-hour full disclosure, we are developing a relational database server dedicated to the patient monitoring system. We are also developing a clinical workstation with which physicians can review and examine the data from patients through various kinds of computer networks far diagnosis and report generation. Portable bedside units with LCD display and wired or wireless data communication capability will be developed in the near future. New parameter modules including cardiac output, capnograph, and other gas analysis functions will be added.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.193-200
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• 2023

Cryptanalysis can be performed by various techniques such as known plaintext attack, differential attack, side-channel analysis, and the like. Recently, many studies have been conducted on cryptanalysis using deep learning. A known-plaintext attack is a technique that uses a known plaintext and ciphertext pair to find a key. In this paper, we use deep learning technology to perform a known-plaintext attack against S-PRESENT, a reduced version of the lightweight block cipher PRESENT. This paper is significant in that it is the first known-plaintext attack based on deep learning performed on a reduced lightweight block cipher. For cryptanalysis, MLP (Multi-Layer Perceptron) and 1D and 2D CNN(Convolutional Neural Network) models are used and optimized, and the performance of the three models is compared. It showed the highest performance in 2D convolutional neural networks, but it was possible to attack only up to some key spaces. From this, it can be seen that the known-plaintext attack through the MLP model and the convolutional neural network is limited in attackable key bits.

• Journal of Distribution Science
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• v.15 no.2
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• pp.79-90
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• 2017

Purpose - Cargo Distribution O2O Business Model is the form of business that connects the cargo and empty cargo-truck based on mobile online platform. In Korean cargo distribution market, FIN(Freight Information Network) is the only model that represents O2O Business Model. The purpose of this paper is investigating the recognition of driver who is the only source of income toward cargo distribution O2O Business Model, and based on the investigated recognition of trucker, suggesting strategic implication. Research design, data, and methodology - PESTLE methodology which is massive environment analysis, and 5 Forces Model when analyze the present and future of cargo distribution O2O business market of industrial structure analysis were used as investigation methodology. Also structured questionnaire was used for trucker's recognition investigation. Based on collected 196 structured effective questionnaires organized with 26 questions were analyzed using statistics package. Results - 51.3% of responded driver is non-differentiated, deprofessionalize form that transport all types of cargo. 95.4% recognize cargo distribution O2O Business Model, FIN is needed, especially during back-hall(94.7%). As a payment method, monthly due is preferred(73%), but it is also needed to pay annual due and pay whenever cargo and cargo-truck are connected(24.5%). Trucker prefer FIN operation corporation which has rich supply(85.2%), and is liberal in supply in any domestic area(75.5%). Conclusions - First, 91% was the member of FIN, and 95% of non-member recognized FIN is needed. 83% of them has the intent to be the member of FIN. Second, besides of monthly due as payment method of FIN, 25% has positive recognition toward new payment method. The new payment method means paying annual due and pay whenever cargo and cargo-truck are connected. Third, because of information imbalance about the cargo and cargo-truck among, operators whose business goal is FIN, it was investigated that transportation fee is low and commission charge of broker is high. The core of Korean Cargo Distribution O2O Business Model, FIN, is online platform that matches cargo and cargo-truck. Therefore, FIN operator should minimize the amount of single transportation of trucker. This study suggests the development of shipper using FIN, diversify distribution channel, suggesting backhaul toward trucker as solution to FIN operator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.235-246
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• 2009

The number of industry wireless networks based on IEEE 802.11 WLAN technology deployed in large outdoor work sites, such as freight container terminal, is increasing these days. Wider service coverage, frequent movements of stations and high requirement on service reliability are main characteristics of these networks compared to the conventional IEEE 802.11 networks used in home, office and school. While the importance of these networks Bets higher, we can hardly find previous studies including concrete analysis on these networks based on actual experiments. We carried out several field experiments at a freight container terminal to analyze its IEEE 802.11 network and found out some problematic situations, such as over 50% retransmission rates and frequent disruption of communication link while a station is moving. We explain why these problematic situations happen and suggest some solutions, such as application of mesh technology, smart handoff based on location and movement pattern and adjustment of signal strength and channel allocation. Methods and tools used in the experiments are also detailed in the paper which may be helpful for similar future studies.

• The Journal of Society for e-Business Studies
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• v.18 no.2
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• pp.205-222
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• 2013

One of the recent important issues in IT fields is the convergence. It had been simply focused on functional convergence of technologyies. However the convergence in terms of businesses or services also has been made in recent years. The convergence between broadcasting and telecommunication industries can be possible because the e-transformation of broadcasting industry based on digital technology such as multimedia and multi-channel, can be combined with the high speed telecommunication network. It is giving a birth of various convergence services such as IPTV. IPTV is a kind of new service that is combined with the convergence of network, contents, and device. Nevertheless the controversy about the scope and the value of this new convergence service has constantly been raised; for example, what is the difference between IPTV and Internet TV? or what are the benefits that customers can have? This study measured the expectation level and the cognitive level of users before and after using the service and analyzed the gap between the importance and the satisfaction of the service. From this study, we proposed the priority of each function by analysing Importance-Performance Analysis(IPA) method to suggest required functions of IPTV service based on N-Screen technology. This study will identify the gap of awareness level between service providers and end users for the functions of broadcasting and telecommunications convergence service and suggest a solution enhancing user satisfaction.