• Journal of KIBIM
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• v.10 no.4
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• pp.60-69
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• 2020

Allowing on-site workers to access information of the construction process can enable task control, data integration, material and resource control. However, in the current practice of the construction industry, the existing methods and scope is quite limited, leading to inefficient management during the construction process. In this research, by adopting cutting edge technologies such as Augmented Reality(AR), digital twins, deep learning and computer vision with wearable AR devices, the authors proposed an AR visualization framework made of virtual components to help on-site workers to obtain information of the construction process with ease of use. Also, this paper investigates wearable AR devices and object detection algorithms, which are critical factors in the proposed framework, to test their suitability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3237-3256
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• 2012

In the context of effective usage of a scarce spectrum resource, emerging wireless communication standards will demand spectrum sharing with existing systems as well as multiple access with higher spectral efficiency. We mathematically analyze the sum throughput of a spectrum sharing space-division multiple access (SDMA) system, which forms a transmit null in the direction of other coexisting systems while satisfying orthogonal beamforming constraints. For a large number of users N, the SDMA throughput scales as log N at high signal-to-noise ratio (SNR) ((J-1) loglog N at normal SNR), where J is the number of transmit antennas. This indicates that multiplexing gain of the spectrum sharing SDMA is $\frac{J-1}{J}$ times less than that of the non-spectrum sharing SDMA only using orthogonal beamforming, whereas no loss in multiuser diversity gain. Although the spectrum sharing SDMA always has lower throughput compared to the non-spectrum sharing SDMA in the non-coexistence scenario, it offers an intriguing opportunity to reuse spectrum already allocated to other coexisting systems.

• Journal of information and communication convergence engineering
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• v.17 no.2
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• pp.149-160
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• 2019

Web applications typically interact with databases. Therefore, it is very crucial to understand which web components access which database resources when maintaining web apps. Existing research identifies interactions between Java web components, such as JavaServer Pages and servlets but does not extract dependencies between the web components and database resources, such as tables and attributes. This paper proposes a dynamic analysis of Java web apps, which extracts such dependencies from a Java web app and represents them as a graph. The key responsibility of our analysis method is to identify when web components access database resources. To fulfill this responsibility, our method dynamically observes the database-related objects provided in the Java standard library using the proxy pattern, which can be applied to control access to a desired object. This study also experiments with open source web apps to verify the feasibility of the proposed method.

• International journal of advanced smart convergence
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• v.13 no.2
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• pp.16-24
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• 2024

With an increase in the relevance of next-generation integrated networking environments, the need to effectively utilize advanced networking techniques also increases. Specifically, integrating Software-Defined Networking (SDN) with Multi-access Edge Computing (MEC) is critical for enhancing network flexibility and addressing challenges such as security vulnerabilities and complex network management. SDN enhances operational flexibility by separating the control and data planes, introducing management complexities. This paper proposes a reinforcement learning-based network path optimization strategy within SDN environments to maximize performance, minimize latency, and optimize resource usage in MEC settings. The proposed Enhanced Proximal Policy Optimization (PPO)-based scheme effectively selects optimal routing paths in dynamic conditions, reducing average delay times to about 60 ms and lowering energy consumption. As the proposed method outperforms conventional schemes, it poses significant practical applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.562-565
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• 2017

In this letter, we consider a 7-step transmission procedure of a large number of machine nodes when they simultaneously request random access to transmit uplink data. We model the radio resource utilization of LTE systems, and analyze the overloaded resources. From the simulation results, we show that the resource of PDCCH becomes significantly overloaded as the number of machine nodes increases in a cell. To alleviate the overload of PDCCH, we allocate radio resource of PDSCH to PDCCH. The result shows that the resource utilization of PDCCH is improved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.707-715
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• 2003

In this paper, we propose a new MAC(Medium Access Control) protocol using Movable-boundary, which tries to guarantee Qos for multimedia traffic in the slotted CDMA system. In this scheme, the traffic scheduler assigns channel resource according to the packet priority per service class and adapts the Movable-boundary concept in which the minimum resource is assigned to each traffic class; the remaining resource if it is available can be assigned dynamically according to the temporal demand of other traffic classes. For performance analysis, we performed computer simulations to obtain throughput and packet loss rate and compared the results with Fixed-boundary system. We observed that the error rate of voice traffic could be maintained below a prescribed value while bursty traffic such as video source shares the same channel. In comparison with Fixed-boundary scheme, our protocol exhibits better throughput and packet loss rate performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.443-444
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• 2021

Security threats to information services are increasingly being developed, and the frequency and damage caused by security threats are also increasing. In particular, security threats occurring inside the organization are increasing significantly, and the size of the damage is also large. A zero trust model has been proposed as a way to improve such a security environment. In the zero trust model, a subject who has access to information resources is regarded as a malicious attacker. Subjects can access information resources after verification through identification and authentication processes. However, the initially proposed zero trust model basically focuses on the network and does not consider the security environment for systems or data. In this study, we proposed a zero trust-based access control mechanism that extends the existing zero trust model to the file system. As a result of the study, it was confirmed that the proposed file access control mechanism can be applied to implement the zero trust model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.1
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• pp.68-78
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• 2013

In this paper, we propose an early spectrum sensing(ESS) as an advance preparation for radio-access trial, which enables multi-mode terminals to access the most appropriate radio-access system in a cloud-conceptual base station system where multiple radio access technologies(RATs) coexist. Prior to a random access to one of RATs, a multi-mode terminal conducts a spectrum sensing over entire frequency bands of whole RATs, then select the RAT with the lowest sensing power, that is likely to have the most available spectrum. Thus, an access failure caused by that the selected RAT has no available radio spectrum could be avoidable in advance. In computer simulation, we consider as various RATs as possible. First, circuit and packet systems are taken into consideration. In addition, the packet systems are classified according to the feasibility of carrier aggregation(CA). In case of terminal, three modes are considered with circuit-only, packet-only, and multi-mode. Subsequently, packet traffic is classified into real-time and non-real-time traffic with three different tolerable delay levels. The simulation includes a call process starting with a call generation and ending up with a resource allocation reflecting individual user's QoS requirements and evaluates the proposed scheme in terms of the successful access probability, system access time, system balancing factor and packet loss probability.

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.12-20
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• 2018

Recently, web-based service software has been used as to combine various information or to share information according to the needs of users and the convergence of specialized fields and individual dependent systems. According to the necessity of the user, the proper service environment and the selective service environment according to the purpose and the needs of the user have been studied in a variety of specialized and combined professional research fields and industries. Software based on cloud systems and web services is being used as a tool for appropriate group and user groups and roles. A service system combined dynamically needs a module to manage a user through internal logic and grant a service access authentication. Therefore, it has been considered various approaches that a user who accesses the system is given a service access authority for a certain period of time. Also, when the deadline is over, the authority that you are given to access system will go through the process of expire the right. In this paper, we define the roles of users who access web services, manage user rights according to each role, and provide appropriate service resources to users according to their rights and session information. We analyzed the procedure of constructing the algorithm for the service according to the procedure of each user accessing the web service, granting the service resource and constructing a new role.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.3
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• pp.573-586
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• 2016

With the adoption of cloud computing, the number of companies that take advantage of cloud computing has increased. Additionally, various of existing service providers have moved their service onto the cloud and provided user with various cloud-based service. The management of user authentication and authorization in cloud-based service technology has become an important issue. This paper introduce a new technique for providing authentication and authorization with other inter-cloud IAM (Identity and Access Management). It is an essential and easy method for data sharing and communication between other cloud users. The proposed system uses the credentials of a user that has already joined an organization who would like to use other cloud services. When users of a cloud provider try to obtain access to the data of another cloud provider, part of credentials from IAM server will be forwarded to the cloud provider. Before the transaction, Access Agreement must be set for granting access to the resource of other Organization. a user can access the resource of other organization based on the control access configuration of the system. Using the above method, we could provide an effective and secure authentication system on the cloud.