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Search Results: 1 - 10 of 107232 matches for " Yang Sun Lee "
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Single port laparoscopic hysterectomy: Feasibility and safety  [PDF]
Soon Pyo Lee, Sun Hye Yang, Chun Hoe Ku, Sung Ho Lee, Jin Woo Shin
Open Journal of Obstetrics and Gynecology (OJOG) , 2013, DOI: 10.4236/ojog.2013.37A2001
Abstract:

Objective: To evaluate the feasibility and safety of single-port laparoscopic hysterectomy comparing with multi-port laparoscopic hysterectomy in treatment of benign uterine diseases. Methods: Data were collected retrospectively by review of the medical records of 252 patients who underwent multi-port or single-port laparoscopic surgery for treatment of benign gynecologic diseases. Laparoscopy assisted vaginal hysterectomy (LAVH) was performed for single-port surgery and LAVH and total laparoscopic hysterectomy (TLH) were performed for multi-port surgery. Demographic variables were collected and analyzed by independent t-test and Pearson Chi-Square test. The primary outcome was analyzed by independent t-test and Fisher’s Exact test. Results: A longer operative time was observed in the multi-port surgery group compared with that of the single-port group (p < 0.05). No difference with respect to change of Hemoglobin between the preoperative level and that of the postoperative first day, the number of days from the operation to discharge, uterine weight, and the rate of laparotomy conversion and complications were observed between the two groups. Conclusion: Single-port laparoscopic hysterectomy for treatment of benign uterine diseases is a safe and feasible method.

Fuzzy Stability of a Quadratic-Additive Functional Equation
Sun Sook Jin,Yang Hi Lee
International Journal of Mathematics and Mathematical Sciences , 2011, DOI: 10.1155/2011/504802
Abstract: We investigate a fuzzy version of stability for the functional equation . 1. Introduction A classical question in the theory of functional equations is “when is it true that a mapping, which approximately satisfies a functional equation, must be somehow close to an exact solution of the equation?” Such a problem, called a stability problem of the functional equation, was formulated by Ulam [1] in 1940. In the next year, Hyers [2] gave a partial solution of Ulam's problem for the case of approximate additive mappings. Subsequently, his result was generalized by Aoki [3] for additive mappings, and by Rassias [4] for linear mappings, to considering the stability problem with the unbounded Cauchy differences. During the last decades, the stability problems of functional equations have been extensively investigated by a number of mathematicians, see [5–16]. In 1984, Katsaras [17] defined a fuzzy norm on a linear space to construct a fuzzy structure on the space. Since then, some mathematicians have introduced several types of fuzzy norm in different points of view. In particular, Bag and Samanta [18], following Cheng and Mordeson [19], gave an idea of a fuzzy norm in such a manner that the corresponding fuzzy metric is of the Kramosil and Michálek type [20]. In 2008, Mirmostafaee and Moslehian [21] introduced for the first time the notion of fuzzy Hyers-Ulam-Rassias stability. They obtained a fuzzy version of stability for the Cauchy functional equation whose solution is called an additive mapping. In the same year, they [22] proved a fuzzy version of stability for the quadratic functional equation whose solution is called a quadratic mapping. Now we consider the quadratic-additive functional equation whose solution is called a quadratic-additive mapping. In [23], Chang et al. obtained a stability of the quadratic-additive functional equation by taking and composing an additive mapping and a quadratic mapping to prove the existence of a quadratic-additive mapping which is close to the given mapping . In their processing, is approximate to the odd part of and is close to the even part of it, respectively. In this paper, we get a general stability result of the quadratic-additive functional equation in the fuzzy normed linear space. To do it, we introduce a Cauchy sequence starting from a given mapping , which converges to the desired mapping in the fuzzy sense. As we mentioned before, in previous studies of stability problem of (1.3), Chang et al. attempted to get stability theorems by handling the odd and even part of , respectively. According to our
Fuzzy Stability of a Functional Equation Deriving from Quadratic and Additive Mappings
Sun Sook Jin,Yang-Hi Lee
Abstract and Applied Analysis , 2011, DOI: 10.1155/2011/534120
Abstract: We investigate a fuzzy version of stability for the functional equation (2
Fuzzy Stability of a General Quadratic Functional Equation
Sun Sook Jin,Yang-Hi Lee
Advances in Fuzzy Systems , 2011, DOI: 10.1155/2011/791695
Abstract: We investigate a fuzzy version of stability for the functional equation in the sense of M. Mirmostafaee and M. S. Moslehian. 1. Introduction and Preliminaries A classical question in the theory of functional equations is “when is it true that a mapping, which approximately satisfies a functional equation, must be somehow close to an exact solution of the equation?”. Such a problem, called a stability problem of the functional equation, was formulated by Ulam [1] in 1940. In the next year, Hyers [2] gave a partial solution of Ulam's problem for the case of approximate additive mappings. Subsequently, his result was generalized by Aoki [3] for additive mappings, and by Rassias [4] for linear mappings, to consider the stability problem with unbounded Cauchy differences. During the last decades, the stability problems of functional equations have been extensively investigated by a number of mathematicians, see [5–15]. In 1984, Katsaras [16] defined a fuzzy norm on a linear space to construct a fuzzy structure on the space. Since then, some mathematicians have introduced several types of fuzzy norm in different points of view. In particular, Bag and Samanta [17], following Cheng and Mordeson [18], gave an idea of a fuzzy norm in such a manner that the corresponding fuzzy metric is of Kramosil and Michálek type [19]. In 2008, Mirmostafaee and Moslehian [20] obtained a fuzzy version of stability for the Cauchy functional equation: In the same year, they [21] proved a fuzzy version of stability for the quadratic functional equation: We call a solution of (1) an additive map, and a solution of (2) is called a quadratic map. Now we consider the functional equation: which is called a general quadratic functional equation. We call a solution of (3) a general quadratic function. Recently, Kim [22] and Jun and Kim [23] obtained a stability of the functional equation (3) by taking and composing an additive map and a quadratic map to prove the existence of a general quadratic function which is close to the given function . In their processing, is approximate to the odd part of , and is close to the even part of it, respectively. In this paper, we get a general stability result of the general quadratic functional equation (3) in the fuzzy normed linear space. To do it, we introduce a Cauchy sequence , starting from a given function , which converges to the desired function in the fuzzy sense. As we mentioned before, in previous studies of stability problem of (3), they attempted to get stability theorems by handling the odd and even part of , respectively. According to
A Fixed Point Approach to the Stability of the Cauchy Additive and Quadratic Type Functional Equation
Sun Sook Jin,Yang-Hi Lee
Journal of Applied Mathematics , 2011, DOI: 10.1155/2011/817079
Abstract: We investigate the stability of the functional equation by using the fixed point theory in the sense of C?dariu and Radu. 1. Introduction In 1940, Ulam [1] raised a question concerning the stability of homomorphisms as follow. Given a group , a metric group with the metric , and a positive number , does there exist a such that if a mapping satisfies the inequality for all then there exists a homomorphism with for all ? When this problem has a solution, we say that the homomorphisms from to are stable. In the next year, Hyers [2] gave a partial solution of Ulam's problem for the case of approximate additive mappings under the assumption that and are Banach spaces. Hyers' result was generalized by Aoki [3] for additive mappings and by Rassias [4] for linear mappings by considering the stability problem with unbounded Cauchy’s differences. The paper of Rassias had much influence in the development of stability problems. The terminology Hyers-Ulam-Rassias stability originated from this historical background. During the last decades, the stability problems of functional equations have been extensively investigated by a number of mathematicians, see [5–12]. Almost all subsequent proofs, in this very active area, have used Hyers' method of [2]. Namely, the mapping , which is the solution of a functional equation, is explicitly constructed, starting from the given mapping , by the formulae or . We call it a direct method. In 2003, C?dariu and Radu [13] observed that the existence of the solution for a functional equation and the estimation of the difference with the given mapping can be obtained from the fixed point theory alternative. This method is called a fixed point method. In 2004, they applied this method [14] to prove stability theorems of the Cauchy functional equation: In 2003, they [15] obtained the stability of the quadratic functional equation: by using the fixed point method. Notice that if we consider the functions defined by and , where is a real constant, then satisfies (1.3), and holds (1.4), respectively. We call a solution of (1.3) an additive map, and a mapping satisfying (1.4) is called a quadratic map. Now we consider the functional equation: which is called the Cauchy additive and quadratic-type functional equation. The function defined by satisfies this functional equation, where are real constants. We call a solution of (1.5) a quadratic-additive mapping. In this paper, we will prove the stability of the functional equation (1.5) by using the fixed point theory. Precisely, we introduce a strictly contractive mapping with the Lipschitz
Fuzzy stability of a mixed type functional equation
Jin Sun,Lee Yang-Hi
Journal of Inequalities and Applications , 2011,
Abstract: In this paper, we investigate a fuzzy version of stability for the functional equation f ( x + y + z ) - f ( x + y ) - f ( y + z ) - f ( x + z ) + f ( x ) + f ( y ) + f ( z ) = 0 in the sense of Mirmostafaee and Moslehian. 1991 Mathematics Subject Classification. Primary 46S40; Secondary 39B52.
Tone-Independent Orthogonalizing Lattice Equalization for Insufficient Cyclic-Prefix OFDM Transmissions
Dong Kyoo Kim,Yang Sun Lee
International Journal of Distributed Sensor Networks , 2013, DOI: 10.1155/2013/281895
Abstract: Tone-independent orthogonalizing lattice per tone equalizer (TOL-PTEQ) is introduced and its convergence is analyzed. Cyclic-prefix redundancy, one of the major drawbacks of orthogonal frequency division multiplexing (OFDM), can be reduced by TOL-PTEQ. Fast convergence and low computational complexity of TOL-PTEQ are also suitable properties for packet-based wireless communications and detections in which OFDM is widely deployed for their modulation technique. 1. Introduction PTEQ was originally proposed for optimizing bit rate of discrete-multitone (DMT) modem in wired communications such as digital subscriber lines (DSLs), where SNR of each tone can be independently maximized [1–4]. In these literatures, computational complexity is a major issue because they should cover a large number of tones, for example, DMTs with 512, 1024, or 2048 tones. Several types of stochastic-gradient algorithms for PTEQ have been proposed to reduce the computational complexity [1, 2]. But convergence rate is considered as a minor issue for DSLs because various DSLs have long training sequences in their initial set-up process. Wireless broadband communication technology is becoming more important for pervasive healthcare solutions as healthcare applications [5–7] are extending their coverage up to global scale as shown in Figure 1 [8]. According to [8], researches on more fast and reliable wireless infrastructures are conducted in order to improve the healthcare services in remote location. Candidate wireless technologies are as follows: IEEE 802.11x, IEEE 802.16x, ETSI HiperLAN, ETSI HiperMAN, and so on. A common feature of the candidates is that they use OFDM as their modulation method which is the promising technology because it is easy to handle the multipath channel problem by using fast Fourier transform. It is also widely utilized for multiple-access method, say OFDMA. It gives multiuser diversity taking advantage of channel frequency selectivity and good scalability over wide range of bandwidth that is achieved just by adjusting FFT size, where FFT stands for fast Fourier transform [9]. OFDM can also be utilized in the field of radar technologies as shown in Figure 2, where the multitone technique can be applied to enhance the radar scanning performance [10]. In this case, various OFDM technologies are essential to the multitone based radar systems. As shown in Figure 2, the radar transmits and receives the radar signal through the antennas. The received signal contains various reflection signals generated by the interfaces between two different layers. To obtain
Melittin restores proteasome function in an animal model of ALS
Eun Jin Yang, Seon Hwy Kim, Sun Choel Yang, Sang Min Lee, Sun-Mi Choi
Journal of Neuroinflammation , 2011, DOI: 10.1186/1742-2094-8-69
Abstract: Melittin is a 26 amino acid protein and is one of the components of bee venom which is used in traditional Chinese medicine to inhibit of cancer cell proliferation and is known to have anti-inflammatory and anti-arthritic effects.The purpose of the present study was to determine if melittin could suppress motor neuron loss and protein misfolding in the hSOD1G93A mouse, which is commonly used as a model for inherited ALS. Meltittin was injected at the 'ZuSanLi' (ST36) acupuncture point in the hSOD1G93A animal model. Melittin-treated animals showed a decrease in the number of microglia and in the expression level of phospho-p38 in the spinal cord and brainstem. Interestingly, melittin treatment in symptomatic ALS animals improved motor function and reduced the level of neuron death in the spinal cord when compared to the control group. Furthermore, we found increased of α-synuclein modifications, such as phosphorylation or nitration, in both the brainstem and spinal cord in hSOD1G93A mice. However, melittin treatment reduced α-synuclein misfolding and restored the proteasomal activity in the brainstem and spinal cord of symptomatic hSOD1G93A transgenic mice.Our research suggests a potential functional link between melittin and the inhibition of neuroinflammation in an ALS animal model.Amyotrophic lateral sclerosis (ALS) is a rapidly progressing and invariably lethal neurodegenerative disease caused by the selective death of lower neurons in the spinal cord and upper motor neurons, and resulting in the paralysis of voluntary muscles [1]. The familial and sporadic forms of the disease are clinically indistinguishable and have been proposed to share a common pathogenesis [1]. Mutations in Cu/Zn superoxide dismutase (SOD1) account for approximately 20% of the cases of the inherited form of ALS (FALS) and represent a major known cause of the disease. Transgenic hSOD1G93A mice, which overexpress mutant hSOD1G93A, develop the cardinal symptoms of ALS in humans, including mus
N,N′-Dimethyl-N,N′-bis(pyridin-2-yl)methanediamine
Moon-Sun Lee,Minyoung Yoon,O-bong Yang,Dong-Heon Lee
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811046320
Abstract: The title compound, C13H16N4, consists of two pyridine rings which are linked by an N,N′-dimethylmethaneamine chain. The pyridine rings adopt a twist conformation and the dihedral angle between them is 60.85 (5)°. The crystal packing is stabilized by weak C—H...π interactions.
Characteristics of Mechanical and Electrical Power Transmission for Small-Scaled Wind Turbine  [PDF]
Kyu-Jin Lee, Hyun-Dai Yang, Sung-Hoon Park, Sung-Do Song, Byung-Sun Kim, Joong-Ho Shin
World Journal of Engineering and Technology (WJET) , 2016, DOI: 10.4236/wjet.2016.43D011
Abstract:
Small-scaled wind turbine is converted to mechanical power of windmill to electric power by generator. However almost all studies seems to have overlooked converting relation of mechanical & electric power. It the reason for was very difficult establishing wind turbine system. In this paper, it is define equation of converting relation of mechanical & electric power. And it is verified by experimental methods. Defined equation will be used in developing electric devices such as inverter and controller in wind turbines. In addition this method can be used in the fields that utilize the rotational power into electrical power through generator.
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