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Adaptive Mode Switching in Correlated Multiple Antenna Cellular Networks
Chulhan Lee,채찬병,Sriram Vishwanath,Robert W. Heath, Jr. 한국통신학회 2009 Journal of communications and networks Vol.11 No.3
This paper proposes an adaptive mode switching algorit- hm between two strategies in multiple antenna cellular networks: A single-user mode and a multi-user mode for the broadcast chan- nel. If full channel state information is available at the base-station, it is known that a multi-user transmission strategy would outper- form all single-user transmission strategies. In the absence of full side information, it is unclear what the capacity achieving method is, and thus there are few criteria to decide which of the myriad possible methods performs best given a system conguration. We compare a single-user transmission and a multi-user transmission with linear receivers in this paper where the transmitter and the re- ceivers have multiple antennas, and nd that neither strategy dom- inates the other. There is instead a transition point between the two strategies. Then, the mode switching point is determined both ana- lytically and numerically for a multiple antenna cellular downlink with correlation between transmit antennas.
Alignment-Free Cancelable Fingerprint Templates Based on Local Minutiae Information
Chulhan Lee,Jeung-Yoon Choi,Kar-Ann Toh,Sangyoun Lee IEEE 2007 part B Vol.37 No.4
<P>To replace compromised biometric templates, cancelable biometrics has recently been introduced. The concept is to transform a biometric signal or feature into a new one for enrollment and matching. For making cancelable fingerprint templates, previous approaches used either the relative position of a minutia to a core point or the absolute position of a minutia in a given fingerprint image. Thus, a query fingerprint is required to be accurately aligned to the enrolled fingerprint in order to obtain identically transformed minutiae. In this paper, we propose a new method for making cancelable fingerprint templates that do not require alignment. For each minutia, a rotation and translation invariant value is computed from the orientation information of neighboring local regions around the minutia. The invariant value is used as the input to two changing functions that output two values for the translational and rotational movements of the original minutia, respectively, in the cancelable template. When a template is compromised, it is replaced by a new one generated by different changing functions. Our approach preserves the original geometric relationships (translation and rotation) between the enrolled and query templates after they are transformed. Therefore, the transformed templates can be used to verify a person without requiring alignment of the input fingerprint images. In our experiments, we evaluated the proposed method in terms of two criteria: performance and changeability. When evaluating the performance, we examined how verification accuracy varied as the transformed templates were used for matching. When evaluating the changeability, we measured the dissimilarities between the original and transformed templates, and between two differently transformed templates, which were obtained from the same original fingerprint. The experimental results show that the two criteria mutually affect each other and can be controlled by varying the control parameters of the changing functions.</P>
A Study of Changeable Biometrics for Fingerprint Recognition
Chulhan Lee,Hyunggu Lee,Jeung-Yoon Choi,Jaihie Kim 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7
To enhance security and privacy in biometric systems, changeable (or cancelable) biometric systems have been developed. These systems can revoke and re-issue biometric data when it is compromised. The proposed method generates changeable fingerprint templates by using a single reference point. In our experiments, performance the proposed method were evaluated and the experimental results showed that the proposed method is a useful way of constructing changeable biometric systems.
Supplement of Conjugated Linoleic Acid Increases Neutrophil Phagocytosis in Pigs
Sang-chulHan,Ji-hounKang,Sung-mokSon,Chung-sooChung,Chul-youngLee,Mhan-pyoYang 한국임상수의학회 2003 한국임상수의학회지 Vol.20 No.4
To examine the in vivo immunostimulating effect of conjugated linoleic acid (CLA) in pigs, the change of peripheral blood cells and the phagocytic response of phagocytes were evaluated. Spayed male pigs, 80kg of average body weight, fed a diet containing either 0.5% 10t-12c CLA or 0.5% CLA mixture (mostly 9c-11t CLA and 10t-12c CLA) for 4 weeks. The change of blood cell values (PCV, WBC, differential count of WBC) and the phagocytic activities of phagocytes were evaluated on week 0, 2, 4, and 5, respectively. There were no change in the PCV values regardless of CLA supplement. The number of WBC, especially neutrophils, in pigs fed a diet with CLA was significantly increased (p<0.05 to 0.01) when compared with control pigs fed a diet without CLA. The phagocytosis of peripheral blood mononuclear cell (MNC) and peripheral blood polymorphonuclear cells (PMN) were analyzed by a flow cytometry system. There was no change in the phagocytic activity of MNC and monocyte-rich cells regardless of CLA supplement. However, the phagocytic activity of PMN composed by approximately 95% neutrophils was remarkably increased (p< 0.05 to 0.01) on week 2, 4, and 5 as compared wth control pigs. These results suggested that supplement of CLA into pigs induces the increase of neutrophil number and the enhancement of neutrophil phagocytosis.
Kim Chulhan,Chun Sung-Youn,Kim Sun Jung,Yang Ki Hwa,Baek Ji Hyeon,Shin Ji Hyeon,Yoo Ji Won,Chang Young Woo,Kang Keon Wook,Hwang Jinwook 대한의학회 2022 Journal of Korean medical science Vol.37 No.19
Background: F-18 Fluorodeoxyglucose positron emission tomography (F-18 FDG PET), which can cover the body from the skull base to the thigh in one scan, is beneficial for evaluating distant metastasis. F-18 FDG PET has interested policymakers because of its relatively high cost. This study investigated the effect of the F-18 FDG PET reimbursement criteria amendment on healthcare behavior in breast cancer using an interrupted time series (ITS) analysis. Methods: We retrospectively analyzed the inpatient and outpatient data from Korea’s Health Insurance Review and Assessment Service (HIRA) from January 1, 2013 to December 31, 2018. ITS analysis was performed for the number of each medical imaging modality and the total medical imaging cost of the breast cancer patients. Results: The annual number of breast cancer patients has been increasing steadily since 2013. The trend of F-18 FDG PET increased before the reimbursement criteria was amended, but intensely decreased immediately thereafter. The chest and abdomen computed tomography scans showed a statistically significant increase immediately after the amendment and kept steadily increasing. A change in the total medical imaging cost for the breast cancer patient claimed every month showed an increasing trend before the amendment (β = 5,475, standard error [SE] = 1,992, P = 0.008) and rapid change immediately after (β = −103,317, SE = 16,152, P < 0.001). However, there was no significant change in the total medical imaging cost at the long-term follow-up (β = −912, SE = 1,981, P = 0.647). Conclusion: Restriction of health insurance coverage for cancer may affect healthcare behaviors. To compensate for it, the policymakers must consider this and anticipate the impact following implementation.
Aryun Kim(Aryun Kim),Jeonghwan Lee(Jeonghwan Lee),Hansol Moon(Hansol Moon),Chulhan Kim(Chulhan Kim),Min Young Yoo(Min Young Yoo),Woo Yoon Park(Woo Yoon Park),Won Dong Kim(Won Dong Kim),Young-Seok Seo( 대한방사선종양학회 2023 Radiation Oncology Journal Vol.41 No.2
Purpose: We aimed to determine whether low-dose radiotherapy (LDRT) is effective in patients with Alzheimer disease (AD). Materials and Methods: We included patients according to the following criteria: probable Alzheimer's dementia according to the New Diagnostic Criteria for Alzheimer’s Disease; confirmation of amyloid plaque deposits on baseline amyloid positron emission tomography (PET); a Korean Mini-Mental State Examination 2nd edition (K-MMSE-2) score of 13–26; and a Global Clinical Dementia Rating (CDR) score of 0.5–2 points. LDRT was performed six times at 0.5 Gy each. Post-treatment cognitive function tests and PET-CT examinations were performed to evaluate efficacy. The medication for AD treatment was maintained throughout the study period. Results: At 6 months after LDRT, neurological improvement was seen in 20% of patients. Patient #2 showed improvement in all domains of the Seoul Neuropsychological Screening Battery II (SNSB-II). Moreover, the K-MMSE-2 and Geriatric Depression Score-Short Form scores improved from 20 to 23 and from 8 to 2, respectively. For patient #3, the CDR score (sum of box score) improved from 1 (4.0) to 1 (3.5) at 3 months follow-up. Moreover, the Z scores for language and related functions, memory, and frontal executive function improved to -2.56, -1.86, and -1.32, respectively at the 6-month follow-up. Two patients complained of mild nausea and mild hair loss during LDRT, which improved after treatment. Conclusion: One of the five patients with AD treated with LDRT experienced a temporary improvement in SNSB-II. LDRT is tolerable in patients with AD. We are currently under follow-up and will conduct cognitive function tests after 12 months after LDRT. A large-scale randomized controlled trial with a longer follow-up period is warranted to determine the effect of LDRT on patients with AD.