• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.574-592
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• 2016

Range-free localization algorithm computes a normal node's position by estimating the distance to anchors which know their actual position. In recent years, reliable anchor selection research has been gained a lot of attention because this approach improves localization accuracy by selecting the only subset of anchors called reliable anchor. The distance estimation accuracy and the geometric shape formed by anchors are the two important factors which need to be considered when selecting the reliable anchors. In this paper, we study the relationship between a relative position of three anchors and localization error. From this study, under ideal condition, which is with zero localization error, we find two conditions for anchor selection, thereby proposing a novel anchor selection algorithm that selects three anchors matched most closely to the two conditions, and the validities of the conditions are proved using two theorems. By further employing the conditions, we finally propose a novel range-free localization algorithm. Simulation results show that the proposed algorithm shows considerably improved performance as compared to other existing works.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권2호
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• pp.98-107
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• 2013

This work describes a 13b 100 MS/s 0.13 um CMOS four-stage pipeline ADC for 3G communication systems. The proposed SHA-free ADC employs a range-scaling technique based on switched-capacitor circuits to properly handle a wide input range of $2V_{P-P}$ using a single on-chip reference of $1V_{P-P}$. The proposed range scaling makes the reference buffers keep a sufficient voltage headroom and doubles the offset tolerance of a latched comparator in the flash ADC1 with a doubled input range. A two-step reference selection technique in the back-end 5b flash ADC reduces both power dissipation and chip area by 50%. The prototype ADC in a 0.13 um CMOS demonstrates the measured differential and integral nonlinearities within 0.57 LSB and 0.99 LSB, respectively. The ADC shows a maximum signal-to-noise-and-distortion ratio of 64.6 dB and a maximum spurious-free dynamic range of 74.0 dB at 100 MS/s, respectively. The ADC with an active die area of 1.2 $mm^2$ consumes 145.6 mW including high-speed reference buffers and 91 mW excluding buffers at 100 MS/s and a 1.3 V supply voltage.

• 한국통신학회논문지
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• 제37권7B호
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• pp.595-605
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• 2012

DV-Hop 위치 인식 기법은 노드가 균일하게 배치된 등방성 토폴로지에서 제안된 알고리즘이다. 노드 간 거리는 홉 수에 비례해서 증가하는 환경에서 홉 당 평균 거리를 사용해서 노드 간 거리를 추정한다. 하지만, 노드의 배치가 균일하지 않아 노드 간 거리가 홉 수에 비례하여 증가하지 않는 환경에서는 DV-hop 기법의 위치 추정의 정확도는 상당히 저하된다. 본 논문에서는 노드의 배치가 불균일한 비등방성 네트워크에서도 위치 추정의 정확도를 높일 수 있는 알고리즘을 제안한다. 비등방성 네트워크에서는 노드 간 경로의 형태가 곡선인 경우가 많기 때문에 노드 간의 거리 추정을 위해 필요한 홉 당 평균 거리가 홉 수 별로 다르다. 이에 제안하는 알고리즘에서는 앵커노드가 홉 수 별로 홉 당 평균 거리를 구하고, 일반 노드는 이러한 정보를 각 앵커노드로부터 전달받아, 앵커노드와 떨어진 홉 수에 따라 다른 홉 당 거리를 사용해 보다 정확하게 위치를 추정하도록 한다. 또한 시뮬레이션을 통해 DV-Hop 알고리즘과의 성능 비교를 통해 제안하는 알고리즘의 우수성을 보인다.

• 농업과학연구
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• 제48권3호
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• pp.455-464
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• 2021

This study was conducted to evaluate meat quality traits, proximate composition, fatty acid profile and sensory attributes of pork produced under free-range and semi-intensive pig rearing systems. Longissimus dorsi muscles from pork carcasses were taken just after the slaughtering of finishing pigs reared under semi-intensive and free-range systems to test the meat quality parameters (pH, color, water holding capacity, and cooking loss), proximate composition (moisture, protein, fat, and ash) and fatty acid profile. Furthermore, the organoleptic properties were evaluated using 30 untrained panelists. The results revealed that the system of rearing did not affect (p > 0.05) the proximate composition, water holding capacity, color, pH and cooking loss of pork along with the fatty acid composition except for vaccenic acid (p < 0.05). The monounsaturated fatty acid (MUFA) content was affected (p < 0.05) by the rearing system while no effects were observed on the unsaturated fatty acid: saturated fatty acid ratio and omega-six to omega-three fatty acids ratios (p > 0.05). No difference was observed (p > 0.05) concerning the sensory attributes although pork obtained from the free-range system had the highest scores. In conclusion, the system of rearing did not show a significant effect on the meat quality parameters, composition and sensory attributes of pork obtained from cross-bred pigs.

• Archives of Reconstructive Microsurgery
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• 제22권2호
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• pp.63-68
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• 2013

Purpose: In case of the failed replantation, if the patients want to preserve the length of amputated stump, toe transfer is the ideal choice. However, reconstruction of these amputated stump with a free flap can be a useful method when the patients refuse sacrificing their toe. Our purpose of this study is to evaluate availability of functional results and patient satisfaction after this procedure. Materials and Methods: From March 2008 to February 2012, we reconstructed the amputated stump with free flap by patients demand. Eleven patients were included, medial plantar artery perforator flap in seven cases and great toe pulp flap in five cases. Follow-up range 12 to 24 months and we evaluate patient satisfaction by using a visual analogue scale (VAS; 1=unsatisfied, 5=excellent) and functional recovery by measuring the range of motion of remaining joint at 12 months after operation. Results: During follow-up period, all transferred free flaps survived and no major complications were noted. Range of motion of remaining joint appeared satisfactory result ($15^{\circ}$ to $100^{\circ}$). The VAS patient satisfaction score for aesthetic were five in six patients, four in four patients, and three in one patient. Conclusion: In case of the failed digital replantation, if patient refuse toe transfer, it could be useful method to reconstruction with the free flap to preserving maximal length of amputated stump.

• 한국해양공학회지
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• 제27권5호
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• pp.16-21
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• 2013

The flow around a circular cylinder advancing beneath the free surface is numerically investigated using a VOF method. The simulations cover Froude numbers in the range of 0.2~0.6 and gap ratios (h/d) in the range of 0.1~2.0, where h is the distance from the free surface to a cylinder, and d is the diameter of a cylinder at Reynolds number 180. It is observed that the vortex suppression effect and surface deformation increase as the gap ratio decreases or the Froude number increases. The most important results of the present study are as follows. The proximity of the free surface causes an initial increase in the Strouhal number and drag coefficient, and the maximum Strouhal number and drag coefficient occur in the range of 0.5~0.7. However, this trend reverses as the gap ratio becomes small, and the lift coefficient increases downward as the gap ratio decreases.

• Radiation Oncology Journal
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• 제34권2호
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• pp.96-105
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• 2016

Purpose: The standard radiation dose for patients with locally rectal cancer treated with preoperative chemoradiotherapy is 45-50 Gy in 25-28 fractions. We aimed to assess whether a difference exists within this dose fractionation range. Materials and Methods: A retrospective analysis was performed to compare three dose fractionation schedules. Patients received 50 Gy in 25 fractions (group A), 50.4 Gy in 28 fractions (group B), or 45 Gy in 25 fractions (group C) to the whole pelvis, as well as concurrent 5-fluorouracil. Radical resection was scheduled for 8 weeks after concurrent chemoradiotherapy. Results: Between September 2010 and August 2013, 175 patients were treated with preoperative chemoradiotherapy at our institution. Among those patients, 154 were eligible for analysis (55, 50, and 49 patients in groups A, B, and C, respectively). After the median follow-up period of 29 months (range, 5 to 48 months), no differences were found between the 3 groups regarding pathologic complete remission rate, tumor regression grade, treatment-related toxicity, 2-year locoregional recurrence-free survival, distant metastasis-free survival, disease-free survival, or overall survival. The circumferential resection margin width was a prognostic factor for 2-year locoregional recurrence-free survival, whereas ypN category was associated with distant metastasis-free survival, disease-free survival, and overall survival. High tumor regression grading score was correlated with 2-year distant metastasis-free survival and disease-free survival in univariate analysis. Conclusion: Three different radiation dose fractionation schedules, within the dose range recommended by the National Comprehensive Cancer Network, had no impact on pathologic tumor regression and early clinical outcome for locally advanced rectal cancer.

• 한국콘텐츠학회논문지
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• 제13권2호
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• pp.52-61
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• 2013

무선 센서 네트워크에서 재난, 환경 모니터링 등에 대한 응용으로써 센서 노드의 지리학적 위치 측정은 매우 중요하다. 이를 위해 무선 센서 네트워크 분야는 Range-free 위치 측정 기법에 대한 연구가 활발하게 진행 중이며, 비 균일 네트워크 환경에서 위치 정확도를 향상하기 위한 중심 극한 정리와 정규 분포에 근거한 위치 측정 기법인 밀집 확률 기법이 제안되었다. 밀집 확률 기법의 경우 노드 통신을 통해 거리를 추정 후 최종 위치를 측정하지만 거리 추정 시 주위 인근 모든 노드가 동일한 1-홉 추정 거리를 갖는 문제점이 발생한다. 따라서 본 논문에서는 이러한 오차를 최소화하기 위해 각 노드마다 거리 추정 후 센싱 반경을 조절하여 2차 지역 거리 평가를 통해 센서의 위치를 측정하는 기법을 제안한다. 성능평가 결과, 제안하는 기법은 밀집 확률 기법에 비해 9% 더 높은 정확도를 보였다. 또한 대표적인 Range-free 위치 측정 기법인 DV-HOP에 비해 48% 더 우수한 위치 정확도를 보였다.

• Journal of the Optical Society of Korea
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• 제19권4호
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• pp.357-362
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• 2015

We examine the principle of a modified Pound-Drever-Hall (PDH) technique to measure the free spectral range of a Fabry-Perot etalon (FPE). The FPE's periodic transmission of phase-modulated light allows us to adopt a sampling theorem to develop a new relationship for the PDH error signal. This leads us to find the key parameters governing the measurement accuracy: the phase modulation index ${\beta}$ and the FPE finesse. Without any additional complexity for background noise reduction, we achieve a measurement accuracy of 0.5 ppm. The improvement is mainly attributed to the wide-band phase modulation approaching ${\beta}=10$, and partly to the use of both reflected and transmitted light from the FPE and good FPE finesse.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제11권4호
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• pp.223-228
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• 2011

In this paper, a novel range-free localization algorithm for anisotropic networks is proposed. In the proposed method, the characteristics of the given network are considered and each sensor node estimates the relation between the hop counts and the geographical distances. Unlike most of the previous localization algorithms, the proposed method performs well not only in the isotropic network but also in the anisotropic networks. The proposed method is applied to both isotropic and anisotropic network topologies and the simulation results demonstrate that the method exhibits excellent and robust performances.