• 대한토목학회논문집
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• 제26권5D호
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• pp.703-708
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• 2006

미국, 일본 등에서는 ITS 장비 성능시험장을 구축하여 정보의 신뢰성 강화, 표준화 및 호환성 확보 등에 활용하고 있다. 본 연구에서는 이러한 외국사례를 검토하여 시험장 선정기준을 제시하고 그에 부합하는 성능시험장을 구축하였으며 ITS 장비 성능시험장의 시범운영을 실시하고 그 시험결과를 분석함으로써 ITS 장비 성능시험장 구축의 중요성을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.299-302
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• 2000

Various types of measuring devices are used for reverse engineering and inspection in different fields of industry such as automotive, aerospace, computer graphics, and home appliance. In order to measure a part easily and efficiently, it is important to select appropriate measuring device considering the characteristics of each measuring machine and part information. In this research, an optimal measuring device selection system using neural networks is proposed. There are two major steps: Firstly, the measuring information such as curvature, normal, type of surface, edge, and facet approximation is extracted from the CAD model. Second, the best suitable measuring device is proposed using the neural network system based on the knowledge of the measuring parameters and the measuring resources. An example of machine selection is implemented to evaluate the performance of the system.

• 대한인간공학회지
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• 제34권1호
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• pp.19-27
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• 2015

Objective: The aim of this study is to investigate how well eye movement times in visual target selection tasks by an eye input device follows the typical Fitts' Law and to compare vertical and horizontal eye movement times. Background: Typically manual pointing provides excellent fit to the Fitts' Law model. However, when an eye input device is used for the visual target selection tasks, there were some debates on whether the eye movement times in can be described by the Fitts' Law. More empirical studies should be added to resolve these debates. This study is an empirical study for resolving this debate. On the other hand, many researchers reported the direction of movement in typical manual pointing has some effects on the movement times. The other question in this study is whether the direction of eye movement also affects the eye movement times. Method: A cursor movement times in visual target selection tasks by both input devices were collected. The layout of visual targets was set up by two types. Cursor starting position for vertical movement times were in the top of the monitor and visual targets were located in the bottom, while cursor starting positions for horizontal movement times were in the right of the monitor and visual targets were located in the left. Results: Although eye movement time was described by the Fitts' Law, the error rate was high and correlation was relatively low ($R^2=0.80$ for horizontal movements and $R^2=0.66$ for vertical movements), compared to those of manual movement. According to the movement direction, manual movement times were not significantly different, but eye movement times were significantly different. Conclusion: Eye movement times in the selection of visual targets by an eye-gaze input device could be described and predicted by the Fitts' Law. Eye movement times were significantly different according to the direction of eye movement. Application: The results of this study might help to understand eye movement times in visual target selection tasks by the eye input devices.

• 대한의용생체공학회:의공학회지
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• 제40권1호
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• pp.20-31
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• 2019

Medical device performance management is an activity that allows a device to be safely used and maintained even after it is put on the market. The purpose of this study is to provide procedures and criteria for selection of medical device items that should manage the safety and performance among medical devices in hospital. Investigate the performance management status of medical devices in hospitals and identify the performance management status by domestic and advanced regulatory agencies. Provides selection procedures and test methods for medical devices subject to performance management in hospitals based on medical device risk management and reliability. In addition, a case study on drug infusion pumps was conducted.

• Journal of Communications and Networks
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• 제18권3호
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• pp.429-438
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• 2016

In this paper, we investigate an interference mitigation scheme by antenna selection in device-to-device (D2D) communication underlaying downlink cellular networks. We first present the closed-form expression of the system achievable rate and its asymptotic behaviors at high signal-to-noise ratio (SNR) and the large antenna number scenarios. It is shown that the high SNR approximation increases with more antennas and higher ratio between the transmit SNR at the base station (BS) and the D2D transmitter. In addition, a tight approximation is derived for the rate and we reveal two thresholds for both the distance of the D2D link and the transmit SNR at the BS above which the underlaid D2D communication will degrade the system rate. We then particularize on the small cell setting where all users are closely located. In the small cell scenario, we show that the relationship between the distance of the D2D transmitting link and that of the D2D interfering link to the cellular user determines whether the D2D communication can enhance the system achievable rate. Numerical results are provided to verify these results.

• Journal of information and communication convergence engineering
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• 제20권3호
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• pp.143-152
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• 2022

The ongoing adoption of 5G will increase the data traffic, throughput, multimedia services, and power consumption for future wireless applications and services, including sensor and mobile networks. Multipath fading on wireless channels also reduces the system performance and increases energy consumption. To address these issues, device-to-device (D2D) and cooperative communications have been proposed. In this study, we propose two inter-clustering models using the relay selection method to improve system performance and increase energy efficiency in cooperative D2D networks. We develop two inter-clustering models and present their respective algorithms. Subsequently, we run a computer simulation to evaluate each model's outage probability (OP) performance, throughput, and energy efficiency. The simulation results show that inter-clustering model II has the lowest OP, highest throughput, and highest energy efficiency compared with inter-clustering model I and the conventional inter-clustering-based multirelay method. These results demonstrate that inter-clustering model II is well-suited for use in 5G overlay D2D and cellular communications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.950-975
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• 2016

Device-to-Device (D2D) communication underlaying cellular networks is a promising add-on component for future radio communication systems. It provides more access opportunities for local device pairs and enhances system throughput (ST), especially when mobile relays (MR) are further enabled to facilitate D2D links when the channel condition of their desired links is unfavorable. However, mutual interference is inevitable due to spectral reuse, and moreover, selecting a suitable transmission mode to benefit the correlated resource allocation (RA) is another difficult problem. We aim to optimize ST of the hybrid system via joint consideration of mode selection (MS) and RA, which includes admission control (AC), power control (PC), channel assignment (CA) and relay selection (RS). However, the original problem is generally NP-hard; therefore, we decompose it into two parts where a hierarchical structure exists: (i) PC is mode-dependent, but its optimality can be perfectly addressed for any given mode with additional AC design to achieve individual quality-of-service requirements. (ii) Based on that optimality, the joint design of MS, CA and RS can be viewed from the graph perspective and transferred into the maximum weighted independent set problem, which is then approximated by our greedy algorithm in polynomial-time. Thanks to the numerical results, we elucidate the efficacy of our mechanism and observe a resulting gain in MR-aided D2D communication.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.357-358
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• 2013

The non-linear characteristics of ON states are important for the application to the high density cross-point memory industry because the sneak current in neighbor cells occurred during reading, erasing, and writing process. Kw of above 20 in ON states, which is the writing current @ Vwrite/the current @ 1/2Vwrite, was required in cross-point ReRAM memory industry. The high current density non-linear IV curve of ZnSe selector was shown and the ALD HfO2 switching device has the linear properties of ON states and the compliance current of 100 uA. To evaluate the performance of the selection device, we connected itto HfO2 switching device in series. The bottom electrode of the selection device was connected to the top electrode of the RRAM. All of the bias was applied with respect to the top electrode of the selection device, whereas the bottom electrode of the RRAM was grounded. In the cross-point application, 1/2Vwrite and -1/2Vwrite were applied to the word-line and bit-line, respectively, which were connected to the selected cell, and a zero bias was applied to the unselected word-lines and bit-lines. The current @ 1/2Vwrite of the unselected cells was blocked by the selection device, thus eliminating the sneak path and obtaining a writing voltage margin. Using this method, the writing voltage margin was analyzed on the basis of the memory size.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권10호
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• pp.2732-2749
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• 2023

Device-to-Device (D2D) communication has received increasing attention and been studied extensively thanks to its advantages in improving spectral efficiency and energy efficiency of cellular networks. This paper proposes a novel relay selection algorithm for multi-hop full-duplex D2D communications underlaying cellular networks. By selecting the relay of each hop in a reverse manner, the proposed algorithm reduces the heavy signaling overhead that traditional relay selection algorithms introduce. In addition, the social domain information of mobile terminals is taken into consideration and its influence on the performance of D2D communications studied, which is found significant enough not to be overlooked. Moreover, simulations show that the proposed algorithm, in absence of social relationship information, improves data throughput by around 70% and 7% and energy efficiency by 64% and 6%, compared with two benchmark algorithms, when D2D distance is 260 meters. In a more practical implementation considering social relationship information, although the proposed algorithm naturally achieves less throughput, it substantially increases the energy efficiency than the benchmarks.

• 한국통신학회논문지
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• 제38A권7호
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• pp.571-579
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• 2013

본 논문은 셀룰러 네트워크에서 D2D (device-to-device) 통신을 고려한 시스템의 에너지 효율적인 모드 선택 기법 (mode selection) 및 파워 할당 기법 (power allocation)을 제안한다. 본 논문에서는 각 단말(device)의 에너지 효율성의 합 측면에서 에너지 효율성 (energy efficiency)을 분석한다. 먼저, 각 단말의 모든 가능한 모드에 대해 에너지 효율을 최대화하는 전송 파워를 계산한다. 제안하는 파워 할당 기법은 시스템 용량 측면에서 최적은 아니지만, 에너지 효율성 측면에서 최적의 성능을 보인다. 제안하는 전송 파워 할당 기법을 기반으로, 모든 가능한 모드에 대해 에너지 효율성을 구한다. 다음 단계로, 모든 가능한 모드 중에서 최대의 에너지 효율성을 갖는 모드를 구하며 동시에 해당 모드의 할당 전송 파워를 도출할 수 있다. 제안 기법은 에너지 효율성 측면에서 최적의 성능을 보이며, 기존 기법에 비해 월등한 성능을 보인다.