• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2024년도 춘계학술발표대회
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• pp.404-407
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• 2024

동형암호는 주목받는 차세대 프라이버시 보존 기술이며, 이를 활용한 신경망 연산 연구들이 많이 수행되고 있다. 여러 체계들 중 TFHE는 비산술 연산을 직접 연산할 수 있으나 다른 체계들보다 매우 느리다는 단점이 있다. 본 연구는 정확도 하락을 최소화하며 성능 개선을 통해 다른 체계인 CKKS보다 빠른 TFHE기반 CNN 연산이 가능하도록 하는 TFHE 비산술 연산의 양자화 기술을 소개한다.

• 한국컴퓨터정보학회논문지
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• 제7권4호
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• pp.33-39
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• 2002

여러대의 CNC Controller를 DNC(Direct Numerical Control) Network Infra를 구축하기 위한 프로그램을 효율적으로 하기 위해 현재 많은 시스템들이 개발되어 사용되고 있다. 그러나 이 시스템들은 원거리 상의 서버 컴퓨터와 머시닝 센터간의 상호 연결이 원만하지 않아 작업에 비효율적인 면이 있고, 또 머시닝 센터에서의 데이터 송·수신에서 일어나는 오류 문제에 대한 시스템으로의 적절한 대처를 할 수가 없다는 문제점이 있다. 그래서, 본 논문에서는 Multi DNC system을 통해 CNC(Computer Numerical Control) 컨트롤러에서 CAD/CAM 서버 컴퓨터의 데이터를 오류 없이 수신 가능한 데이터 원격 제어 시스템을 구성하고자 하였다. 이 데이터 원격 제어 시스템의 주요 장점으로는 머시닝 센터에서 운영자가 쉽게 CAD/CAM 서버 컴퓨터에 저장된 NC 데이터 호출과 송출이 자유롭고, 서버 컴퓨터와 공작기계간의 상호 대화가 없이도 머시닝센터에서의 원격 제어가 가능하다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2005년도 춘계학술발표대회 및 제8회 신소재 심포지엄 논문개요집
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• pp.126-126
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• 2005

• Journal of Magnetics
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• 제19권1호
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• pp.55-58
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• 2014

We have synthesized ferromagnetic ${\tau}$-phase $Mn_{54}Al_{46}/{\alpha}$-phase $Fe_{65}Co_{35}$ composite by annealing a mixture of paramagnetic ${\varepsilon}$-phase $Mn_{54}Al_{46}$ and ferromagnetic ${\alpha}$-phase $Fe_{65}Co_{35}$ particles at $650^{\circ}C$. The volume fraction ($f_h$) of hard ${\tau}$-phase $Mn_{54}Al_{46}$ of the composite was varied from 0 to 1. During the annealing, magnetic phase transformation occurred from paramagnetic ${\varepsilon}$-phase to ferromagnetic ${\tau}$-phase $Mn_{54}Al_{46}$. The magnetization and coercivity of the composite monotonically decreased and increased, respectively, as the $f_h$ increased. These results are in good agreement with our proposed composition dependent coercivity and modified magnetization equations.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.3.1-3.1
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• 2008

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.174-179
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• 2017

We designed the CMOS analog integrate and fire (I&F) neuron circuit for driving memristor based on resistive-switching random access memory (RRAM). And we fabricated the RRAM device that have $HfO_2$ switching layer using atomic layer deposition (ALD). The RRAM device has gradual set and reset characteristics. By spice modeling of the synaptic device, we performed circuit simulation of synaptic device and CMOS neuron circuit. The neuron circuit consists of a current mirror for spatial integration, a capacitor for temporal integration, two inverters for pulse generation, a refractory part, and finally a feedback part for learning of the RRAM. We emulated the spike-timing-dependent-plasticity (STDP) characteristic that is performed automatically by pre-synaptic pulse and feedback signal of the neuron circuit. By STDP characteristics, the synaptic weight, conductance of the RRAM, is changed without additional control circuit.

• Journal of information and communication convergence engineering
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• 제18권2호
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• pp.123-131
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• 2020

After observing that most tourists plan to complete their visits to multiple cultural heritage sites within one day, we surmised that for many museum visitors, the foremost thought is with regard to the amount of time is to be spent at each location and how they can maximize their enjoyment at a site while still balancing their travel itinerary? Recommendation systems in e-commerce are built on knowledge about the users' previous purchasing history; recommendation systems for museums, on the other hand, do not have an equivalent data source available. Recent solutions have incorporated advanced technologies such as algorithms that rely on social filtering, which builds recommendations from the nearest identified similar user. Our paper proposes a different approach, and involves providing dynamic recommendations that deploy social filtering as well as content-based filtering using term frequency-inverse document frequency. The main challenge is to overcome a cold start, whereby no information is available on new users entering the system, and thus there is no strong background information for generating the recommendation. In these cases, our solution deploys statistical methods to create a recommendation, which can then be used to gather data for future iterations. We are currently running a pilot test at Chao Samphraya national museum and have received positive feedback to date on the implementation.

• Journal of Magnetics
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• 제17권1호
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• pp.1-5
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• 2012

The coercivity of a single 27 nm-spherical barium ferrite (S-BaFe) particle was simulated using three models: 1) Gibbs free energy (GFE), 2) Landau-Lifshitz-Gilbert (LLG), and 3) Stoner-Wohlfarth (S-W). Spherically and hexagonally shaped particles were used in the GFE and LLG simulations to investigate coercivity with the different shape anisotropies. The effect of shape was not included in the S-W model. It was found that the models using a spherical shape resulted in a coercivity higher than the models using the hexagonal shape with both shapes having the same diameter. The coercivity estimated with the S-W model was approximately the same as that for the spherical-shape models, which indicates that spherical shape has no significant effect on the particle's coercivity at nanoscale.

• Journal of Communications and Networks
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• 제17권5호
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• pp.453-462
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• 2015

Body area networks (BANs) have emerged as an enabling technique for e-healthcare systems, which can be used to continuously and remotely monitor patients' health. In BANs, the data of a patient's vital body functions and movements can be collected by small wearable or implantable sensors and sent using shortrange wireless communication techniques. Due to the shared wireless medium between the sensors in BANs, it may be possible to have malicious attacks on e-healthcare systems. The security and privacy issues of BANs are becoming more and more important. To provide secure and correct association of a group of sensors with a patient and satisfy the requirements of data confidentiality and integrity in BANs, we propose a novel enhanced secure sensor association and key management protocol based on elliptic curve cryptography and hash chains. The authentication procedure and group key generation are very simple and efficient. Therefore, our protocol can be easily implemented in the power and resource constrained sensor nodes in BANs. From a comparison of results, furthermore, we can conclude that the proposed protocol dramatically reduces the computation and communication cost for the authentication and key derivation compared with previous protocols. We believe that our protocol is attractive in the application of BANs.

• International Journal of Computer Science & Network Security
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• 제23권1호
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• pp.78-88
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• 2023

Medication safety and medicine delivery challenge the well-being of the elderly and the management of the elderly center. With the outbreak of COVID-19, the elderly in the care center were challenged by the inconvenience of the medication restocking. The purpose of this paper accentuates the importance of the design and development of an UAV-based Smart Medicine Case (UAV-SMC) to improve the performance of medication management and medicine delivery in the elderly center. The researchers came up with the design of UAV-SMC in the light of the UAV and IoT technology to improve the performance of both Medication Practice Management (MPM) and Low Inventory Detection and Delivery (LIDD). Based on the result, with UAV-SMC, the performance of both MPM and LIDD was significantly improved. The UAV-SMC improves the efficacy of medication management in the elderly center by 26.97 to 149.83 seconds for each medication practice and 9.03 mins for each time of medicine delivery in Subang Jaya Malaysia. This paper only investigates the adoption of UAV-SMC in the content of elderly center rather than other industries. The authors consider integrating the UAV-SMC with the e-pharmacy system in the future. In conclusion, the UAV-SMC has significantly improved the medication management and guard the safety of elderly and caretaker in the elderly in the post-pandemic times.