• Journal of The Korea Institute of Healthcare Architecture
• /
• v.25 no.2
• /
• pp.51-62
• /
• 2019

Purpose: This study aims to examine spatial characteristics of ambulatory care department Chronologically through case studies; and to consider the social implication of these spatial changes. Methods: In this study, a total of eight ambulatory care departments, one or two for each period, were selected in order to analyze the spatial characteristics. Results: First, since the 1990s, the outpatient department of the US has been changed into a patient-centered space by providing high quality outpatient medical services through individual exam room planning. Second, the exam room has been changed from open/semi-open/group exam room to individual exam room since 1990, and the trend is shifting from the cluster type to the modular type consisting of universal exam rooms in order to achieve the flexibility of exam room. Third, the diagnostic/testing area has been deployed to the ambulatory clinic to enable 'one-stop shopping' for patients-centered care since 1990s, however, it has been disappearing since 2000 due to Reduce medical expenses. Fourth, the Central Nursing Station type first appeared in the outpatient department In the 2000s, followed by the type of decentralized nursing station type since 2010s. And fifth, the area of medical support has been placing to be concentrated on one place due to the Lean Design strategy since 2010. Implications: In the future, it is expected that Korea will be more focused on efficiency, visual control, and flexibility in the planning of the ambulatory care department as in the case of the United States.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.31 no.4
• /
• pp.637-659
• /
• 2021

Since the creation of the first Bitcoin blockchain in 2009, the number of cryptocurrency users has steadily increased. However, the number of hacking attacks targeting assets stored in these users' cryptocurrency wallets is also increasing. Therefore, we evaluate the security of the wallets currently on the market to ensure that they are safe. We first conduct threat modeling to identify threats to cryptocurrency wallets and identify the security requirements. Second, based on the derived security requirements, we utilize attack trees and Bayesian network analysis to quantitatively measure the risks inherent in each wallet and compare them. According to the results, the average total risk in software wallets is 1.22 times greater than that in hardware wallets. In the comparison of different hardware wallets, we found that the total risk inherent to the Trezor One wallet, which has a general-purpose MCU, is 1.11 times greater than that of the Ledger Nano S wallet, which has a secure element. However, use of a secure element in a cryptocurrency wallet has been shown to be less effective at reducing risks.

• KIPS Transactions on Software and Data Engineering
• /
• v.10 no.4
• /
• pp.143-152
• /
• 2021

It is very important to learn behavioral policies that allow multiple agents to work together organically for common goals in various real-world applications. In this multi-agent reinforcement learning (MARL) environment, most existing studies have adopted centralized training with decentralized execution (CTDE) methods as in effect standard frameworks. However, this multi-agent reinforcement learning method is difficult to effectively cope with in a dynamic environment in which new environmental changes that are not experienced during training time may constantly occur in real life situations. In order to effectively cope with this dynamic environment, this paper proposes a novel multi-agent reinforcement learning system, C-COMA. C-COMA is a continual learning model that assumes actual situations from the beginning and continuously learns the cooperative behavior policies of agents without dividing the training time and execution time of the agents separately. In this paper, we demonstrate the effectiveness and excellence of the proposed model C-COMA by implementing a dynamic mini-game based on Starcraft II, a representative real-time strategy game, and conducting various experiments using this environment.

• Journal of Internet Computing and Services
• /
• v.20 no.5
• /
• pp.9-18
• /
• 2019

Android Application Package (APK) is vulnerable to repackaging attacks. Therefore, obfuscation technology was applied inside the Android APK file to cope with repackaging attack. However, as more advanced reverse engineering techniques continue to be developed, fake Android APK files to be released. A new approach is needed to solve this problem. A blockchain is a continuously growing list of records, called blocks, which are linked and secured using cryptography. Each block typically contains a cryptographic hash of theprevious block, a timestamp and transaction data. Once recorded, the data inany given block cannot be altered retroactively without the alteration of all subsequent blocks. Therefore, it is possible to check whether or not theAndroid Mobile APK is forged by applying the blockchain technology. In this paper, we construct a discrimination DApp (Decentralized Application) against forgery Android Mobile APK by recording and maintaining the legitimate APK in the consortium blockchain framework like Hyperledger Fabric by Composer. With proposed DApp, we can prevent the forgery and modification of the appfrom being installed on the user's Smartphone, and normal and legitimate apps will be widely used.

• Journal of the Architectural Institute of Korea Planning & Design
• /
• v.34 no.8
• /
• pp.105-116
• /
• 2018

The architecture reflects geographical characteristics such as geographical environments and climate, it has the characteristics and cultural characteristics of the region that has been constructed. Hansen Village constructed in Period of Japanese Occupation at 'Sorok-Island' in Go-heung, Jeollanam-do was also based on this point. The village, which is a ward of Sorok-Island Province, consists of a village in which patients are self-sufficient in economic and social activities, unlike the modern hospital systems where patients and treatments are concentrated in a single room. Additionally, the facilities for patient acceptance were gradually expanded, with limited interaction with external. Sorok-island shows the expansion of the village center where the new village is formed with the increase of the number of the early adopters in the 1910s and the accommodation facility is built, and it gradually increases the necessary space by opening and repairing the existing facilities by the 1990s Change. In addition, the spatial composition of the village can be divided into three types : decentralized, centralized and single-shift ; it has the same causal relationship as the village's formation. The purpose of this study is identifying the uniqueness of Sorok-Island by analyzing the correlation between the formation of a village to accommodate Hansen Patients in Sorok-Island and the spatial Component Factor.

• The Journal of the Korea Contents Association
• /
• v.21 no.5
• /
• pp.592-606
• /
• 2021

This study examines the impact of knowledge management strategies and knowledge management determinants for each type of knowledge management of a company on knowledge activities, and because each company's situation and conditions are different, it is necessary to approach each knowledge management type. The analysis was conducted using the SPSS 18.0 program targeting 81 companies that have introduced knowledge management systems or knowledge management by categorizing them into technology-oriented and combined types. The result is that Initial types are based on changes in organizational structure and active adoption of information technology, and the Organizational knowledge centers use management systems (CEO support, performance compensation system, education and training system) and infrastructure building and information technology to maximize individual knowledge. The Information technology-oriented types rely more on information technology such as infrastructure building and information technology use rather than organizational knowledge. and the Combination type is understood as an educational and training system and decentralized organizational structure for the overall expansion of the organization. Through this study, effective and significant strategies, knowledge management determinants, and knowledge activities for each type were presented.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.17 no.4
• /
• pp.131-136
• /
• 2007

Ad hoc networks enable efficient resource aggregation in decentralized manner, and are inherently scalable and fault-tolerant since they do not depend on any centralized authority. However, lack of a centralized authority prompts many security-related challenges. Moreover, the dynamic topology change in which network nodes frequently join and leave adds a further complication in designing effective and efficient security mechanism. Security services for ad hoc networks need to be provided in a scalable and fault-tolerant manner while allowing for membership change of network nodes. In this paper, we investigate distributed certification mechanisms using a threshold cryptography in a way that the functions of a CA(Certification Authority) are distributed into the network nodes themselves and certain number of nodes jointly issue public key certificates to future joining nodes. In the process, we summarize one interesting report [5] in which the recently proposed RSA-based ad hoc signature scheme, called URSA, contains unfortunate yet serious security flaws. We then propose new scheme by fixing their security flaws.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.43 no.4
• /
• pp.168-177
• /
• 2020

In recent years, importance of blockchain systems has been grown after success of bitcoin. Distributed consensus algorithm is used to achieve an agreement, which means the same information is recorded in all nodes participating in blockchain network. Various algorithms were suggested to resolve blockchain trilemma, which refers conflict between decentralization, scalability, security. An algorithm based on Byzantine Agreement among Decentralized Agents (BADA) were designed for the same manner, and it used limited committee that enables an efficient consensus among considerable number of nodes. In addition, election of committee based on Proof-of-Nonce guarantees decentralization and security. In spite of such prominence, application of BADA in actual blockchain system requires further researches about performance and essential features affecting on the performance. However, performance assessment committed in real systems takes a long time and costs a great deal of budget. Based on this motivation, we designed and implemented a simulator for measuring performance of BADA. Specifically, we defined a simulation framework including three components named simulator Command Line Interface, transaction generator, BADA nodes. Furthermore, we carried out response surface analysis for revealing latent relationship between performance measure and design parameters. By using obtained response surface models, we could find an optimal configuration of design parameters for achieving a given desirable performance level.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.4
• /
• pp.183-189
• /
• 2021

In recent years, active research has been devoted toward developing a monitoring system using ambient vibration data in order to quantitatively determine the deterioration occurring in a structure over a long period of time. This study developed a low-cost edge computing system that detects the abnormalities in structures by utilizing the dynamic characteristics acquired from the structure over the long term for ensemble learning. The system hardware consists of the Raspberry Pi, an accelerometer, an inclinometer, a GPS RTK module, and a LoRa communication module. The structural abnormality detection afforded by the ensemble learning using dynamic characteristics is verified using a laboratory-scale structure model vibration experiment. A real-time distributed processing algorithm with dynamic feature extraction based on the experiment is installed on the Raspberry Pi. Based on the stable operation of installed systems at the Community Service Center, Pohang-si, Korea, the validity of the developed system was verified on-site.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.2
• /
• pp.445-466
• /
• 2022

As everything linking to the internet, people can subscribe to various services from a service provider to facilitate their lives through the Internet of Things (IoT). An obligatory thing for the service provider is that they should push the service data safely and timely to multiple IoT terminal devices regularly after the IoT devices accomplishing the service subscription. In order to control the service message received by the legal devices as while as keep the confidentiality of the data, the public key encryption algorithm is utilized. While the existing public encryption algorithms for push service are too complicated for IoT devices, and almost of the current subscription schemes based on push mode are relying on centralized organization which may suffer from centralized entity corruption or single point of failure. To address these issues, we design a secure subscription-push service scheme based on blockchain and edge computing in this article, which is decentralized with secure architecture for the subscription and push of service. Furthermore, inspired by broadcast encryption and multicast encryption, a new encryption algorithm is designed to manage the permissions of IoT devices together with smart contract, and to protect the confidentiality of push messages, which is suitable for IoT devices. The edge computing nodes, in the new system architecture, maintain the blockchain to ensure the impartiality and traceability of service subscriptions and push messages, meanwhile undertake some calculations for IoT devices with limited computing power. The legalities of subscription services are guaranteed by verifying subscription tags on the smart contract. Lastly, the analysis indicates that the scheme is reliable, and the proposed encryption algorithm is safe and efficient.