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Search Results: 1 - 10 of 10304 matches for " Yoon Kyung Park "
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On the Torsion Subgroups of Certain Elliptic Curves over Q  [PDF]
Yoon Kyung Park
Advances in Pure Mathematics (APM) , 2013, DOI: 10.4236/apm.2013.32043

Let E be an elliptic curve over a given number field . By Mordells Theorem, the torsion subgroup of E defined over Q is a finite group. Using Lutz-Nagell Theorem, we explicitly calculate the torsion subgroup E(Q)tors for certain elliptic curves depending on their coefficients.

Bernoulli Identities and Combinatoric Convolution Sums with Odd Divisor Functions
Daeyeoul Kim,Yoon Kyung Park
Abstract and Applied Analysis , 2014, DOI: 10.1155/2014/890973
Abstract: We study the combinatoric convolution sums involving odd divisor functions, their relations to Bernoulli numbers, and some interesting applications. 1. Introduction The Bernoulli polynomials , which are usually defined by the exponential generating function play an important role in different areas of mathematics, including number theory and the theory of finite differences. It is well known that are rational numbers. It can be shown that for and is alternatively positive and negative for even . The are called Bernoulli numbers. Let denote the set of positive integers. Further, let , where . Throughout this paper, we define divisor functions as follows: We also make use of the following convention: Ramanujan [1] proved that using elementary arguments. Let be the complex upper half plane and let be for . Denote by the Dedekind function and by the th coefficient of . Alaca and Williams [2] proved that It turns out that we need not only divisor functions but also the coefficients of certain modular functions. For other divisor functions, Hahn [3] showed that and Glaisher [4–6] extended Besgue’s formula by replacing in the convolution sum in (4) by other sums ; for example, Recently, the combinatorial convolution sum is studied [7–10]. In [10] Williams proved the following. Proposition 1. Let and . Then Cho et al. found out the linear sum for combinatorial convolution sum of in [7]. Proposition 2. For and , one has where Denote by . The generating function ??of is an even function and is zero for all odd positive integer . The aim of this paper is to study two combinatorial convolution sums of the analogous type of Proposition 2. When we write the convolution sums as linear sum of divisor function, in the result by Williams the coefficients are and ours are . More precisely, we prove the following theorems. Theorem 3. For and , Equation (7) is a special case when for the following theorem because and . Theorem 4. For and , Remark 5. The product of two modular forms is another modular form of bigger weight. The dimension of space of modular forms on is approximately linear for and the space generated by generating functions of divisor functions is clearly 2 as grows. More precisely speaking, for the Eisenstein series and which will be defined in Section 2 where is the space of cusp form of weight on and it is orthogonal complement of?? in?? . Since?? = and = , for suitable constants?? . On the other hand, Theorems 3 and 4 show that the combinatorial convolution sums are written as only divisor functions; that is, The disappearance of is observed in Examples
Effect of Hoechunyangkyeok-San Extract on Melanogenesis  [PDF]
Mi Jin Kim, Taek Kyu Jung, Hyun-Chul Park, Kyung-Sup Yoon
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2016, DOI: 10.4236/jcdsa.2016.63011
Abstract: Forsythia fructus has been shown to have antioxidative, anti-inflammatory, antibacterial, anti-aging and whitening effects. Hoechunyangkyeok-san (Forsythia viridissima-prescription) is a traditional herbal medicine, which has been clinically used for treating febrile and inflammatory disorders. This work was carried out to investigate the skin whitening effects of Forsythia viridissima-prescription extract (a hydrolyzed extract of Hoechunyangkyeok-san: SID White HYC) on skin. The effects of SID White HYC were assessed the melanin contents in B161 melanoma cells and the pigmented equivalent with HMB45 and Fontana Masson staining in 3D skin model. Then, we examined the expression of major pigment enzymes regulating melanin synthesis and melanosome transport related proteins in B16F1 cells. SID White HYC significantly inhibited the melanin synthesis (56.7% and 30.6% inhibition at 100 μg/mL, intracellular and secreted, respectively) in B16F1 cells and 3D skin model. In addition, western blotting analysis showed that SID White HYC reduced the expression of melanin synthesis and melanosome transport related proteins in B16F1 cells. In clinical trials, the cream containing 0.05% SID White HYC showed skin depigmentation effect without any irritation. These results suggest that SID White HYC may be useful inhibition of melanogenesis and melanosome transport. Therefore, SID White HYC may have potential as a skin-whitening ingredient in cosmetics.
Lyapunov Exponent and the Solid-Fluid Phase Transition
Kyung-Hoon Kwon,Byung-Yoon Park
Physics , 1997, DOI: 10.1063/1.474879
Abstract: We study changes in the chaotic properties of a many-body system undergoing a solid-fluid phase transition. To do this, we compute the temperature dependence of the largest Lyapunov exponents $\lambda_{max}$ for both two- and three-dimensional periodic systems of $N$-particles for various densities. The particles interact through a soft-core potential. The two-dimensional system exhibits an apparent second-order phase transition as indicated by a $\lambda$-shaped peak in the specific heat. The first derivative of $\lambda_{max}$ with respect to the temperature shows a peak at the same temperature. The three-dimensional system shows jumps, in both system energy and $\lambda_{max}$, at the same temperature, suggesting a first-order phase transition. Relaxation phenomena in the phase-transition region are analyzed by using the local time averages.
Total Hip Arthroplasty after Treatment of Pseudojoint Infection in a Patient with a Highly Dislocated Hip
Kyung-Soon Park,Jong-Keun Seon,Seon-Yoon Nah,Taek-Rim Yoon
Case Reports in Orthopedics , 2013, DOI: 10.1155/2013/947121
Abstract: Infection at the pseudoacetabulum in a patient with a high hip dislocation has not been reported previously in the English literature. We report a case of total hip arthroplasty in a 28-year-old female who presented to us with hip pain following debridement of the infected pseudojoint in a case of neglected developmental dysplasia of the hip. The infection was treated with thorough debridement and drainage. However, even after achieving complete infection control, this patient complained of disabling right hip joint pain. Total hip arthroplasty with subtrochanteric osteotomy was performed to relieve the pain and improve gait. After surgery, the patient's symptoms were relieved. We consider that in this case of acute pseudojoint infection simple arthrotomy and debridement combined with irrigation and drainage provide effective treatment. But muscle weakness and more increased joint laxity can cause hip pain even after infection control. So total hip arthroplasty is likely to be necessary after the infection has been controlled in a patient with a highly dislocated hip. 1. Introduction High dislocation of adult hip as sequelae of developmental dysplasia of the hip (DDH) presents with a distorted femoral head located in the pseudoacetabulum and leg length discrepancy [1–4]. Furthermore, contracture and shortening of surrounding neurovascular structures increase the likelihood of injury during surgery [3]. These problems have been frequently discussed, but infection at the pseudoacetabulum in high hip dislocation and its treatment have not been previously reported in the English literature. Here, we report a patient with an acute infection at the pseudoacetabulum with high hip dislocation. After the treatment of the infection, this patient was underwent total hip arthroplasty (THA). The patient agreed that her case data could be submitted for publication. 2. Case Report A 28-year-old woman was transferred to our emergency room for severe right hip pain and a febrile sensation of 5-day duration. A physical examination of the right hip joint revealed swelling, tenderness, and painful range of motion limitation. Radiography showed right hip high dislocation and dysplasia with small femoral canal and head and pseudoacetabular joint (Figure 1(a)). MRI showed inflammatory reaction with joint effusion and synovial thickening with rim enhancement (Figures 1(b) and 1(c)). Her laboratory findings revealed white blood cells (WBCs) 8700/mm3 (neutrophils 83.8%), erythrocyte sedimentation rate (ESR) 93?mm/hr, and C-reactive protein (CRP) 13.45?mg/dL, suggesting the
Striping and Scheduling for Large Scale Multimedia Servers
Kyung-Oh Lee,Jun-Ho Park,Yoon-Young Park,

计算机科学技术学报 , 2004,
Abstract: When designing a multimedia server, several things must be decided: which scheduling scheme to adopt, how to allocate multimedia objects on storage devices, and the round length with which the streams will be serviced. Several problems in the designing of large-scale multimedia servers are addressed, with the following contributions: (1) a striping scheme is proposed that minimizes the number of seeks and hence maximizes the performance; (2) a simple and efficient mechanism is presented to find the optimal striping unit size as well as the optimal round length, which exploits both the characteristics of VBR streams and the situation of resources in the system; and (3) the characteristics and resource requirements of several scheduling schemes are investigated in order to obtain a clear indication as to which scheme shows the best performance in realtime multimedia servicing. Based on our analysis and experimental results, the CSCAN scheme outperforms the other schemes. It is believed that the results are of value in the design of effective large-scale multimedia servers.
Use of serum squamous cell carcinoma antigen for follow-up monitoring of cervical cancer patients who were treated by concurrent chemoradiotherapy
Sang Yoon, Kyung Shin, Joo-Young Kim, Sang Seo, Sang-Yoon Park, Sung Moon, Kwan Cho
Radiation Oncology , 2010, DOI: 10.1186/1748-717x-5-78
Abstract: The records of 112 patients with cervical cancer were reviewed. Serum SCC-Ag levels were measured at regular follow-up visits. A SCC-Ag level of 2 ng/mL was considered the upper limit of normal. Biochemical failure was defined as two consecutively increasing SCC-Ag values above normal. Recurrent disease was confirmed by histologic and radiographic studies.Eighteen patients (16%) developed recurrent disease. Sixteen patients had initially elevated SCC-Ag, post-treatment normalization of SCC-Ag, and tumor recurrence. The SCC-Ag difference (ΔSCC-Ag), defined as the difference between the last value after two consecutively increases above normal and the value immediately before the elevation, had good clinical performance in predicting cancer recurrence. The cutoff value of ΔSCC-Ag was 0.95 ng/mL.SCC-Ag is a relatively good method for the detection of disease recurrence in patients with cervical cancer who were treated by concurrent chemoradiotherapy.Radiotherapy has maintained its place as the cornerstone of therapy for many decades for uterine cervical cancer. Recently, the results of several randomized trials have recommended the concomitant administration of chemotherapy and radiotherapy as a standard treatment for patients with locally advanced cervical cancer [1-3]. Although this combination treatment plays a role in improving disease control, many patients suffer from tumor recurrence during the follow-up period. Therefore, the identification of prognostic factors associated with disease course and outcome following chemoradiotherapy may help to guide the development of more effective treatments and prevent tumor recurrence.Over the past decade, several serum markers have been investigated to search for additional prognostic parameters that could be used, to monitor the treatment response, and detect the recurrence in patients with cervical cancer. In particular, the squamous cell carcinoma antigen (SCC-Ag) is the most commonly used tumor marker for cervical canc
Gain-Scheduled Complementary Filter Design for a MEMS Based Attitude and Heading Reference System
Tae Suk Yoo,Sung Kyung Hong,Hyok Min Yoon,Sungsu Park
Sensors , 2011, DOI: 10.3390/s110403816
Abstract: This paper describes a robust and simple algorithm for an attitude and heading reference system (AHRS) based on low-cost MEMS inertial and magnetic sensors. The proposed approach relies on a gain-scheduled complementary filter, augmented by an acceleration-based switching architecture to yield robust performance, even when the vehicle is subject to strong accelerations. Experimental results are provided for a road captive test during which the vehicle dynamics are in high-acceleration mode and the performance of the proposed filter is evaluated against the output from a conventional linear complementary filter.
Use of the foraging area by captive bred oriental storks (Ciconia boyciana) in a closed semi natural paddy field
Jongmin Yoon,Sang-Hee Na,Su-Kyung Kim,Shi-Ryong Park
Journal of Ecology and Field Biology , 2012,
Abstract: Rice paddy fields have been recognized as an alternative habitat for avian wetland foragers, and fish-rice farms havebecome a new tool in improving the abundance of aquatic animals. However, the use of the habitats by avian foragers,particularly by oriental storks (Ciconia boyciana), was not well understood. In the present study, we investigated how afish-rice farm influenced the abundance of aquatic animals and documented the foraging behavior of the two captivebred oriental storks in a closed semi-natural paddy field. Our results showed that the fish refuge pond (water depth 40cm) had a higher abundance of fish whereas the areas planted with rice (water depth 20 cm) had more tadpoles and someaquatic insects. The two captive bred oriental storks captured mostly fish and aquatic insects in the rice-planted area andmostly fish in the fish refuge pond. The two oriental storks had higher foraging success and spent more time for foragingin the rice-planted area than in the fish refuge pond. This result suggests that the oriental storks might prefer foraging inthe area with fish, aquatic insects, and amphibians under a greater success rate presumably due to shallow water depthin the paddy fields with a fish-rice farm.
Channel-mediated astrocytic glutamate release via Bestrophin-1 targets synaptic NMDARs
Han Kyung-Seok,Woo Junsung,Park Hyungju,Yoon Bong-June
Molecular Brain , 2013, DOI: 10.1186/1756-6606-6-4
Abstract: Background Astrocytes regulate neuronal excitability and synaptic activity by releasing gliotransmitters such as glutamate. Our recent study demonstrated that astrocytes release glutamate upon GPCR activation via Ca2+ activated anion channel, Bestrophin-1 (Best1). The target of Best1-mediated astrocytic glutamate has been shown to be the neuronal NMDA receptors (NMDAR). However, whether it targets synaptically or extra-synaptically localized NMDAR is not known. Findings We recorded spontaneous miniature excitatory postsynaptic currents (mEPSCs) from CA1 pyramidal cells to test whether Best1-mediated astrocytic glutamate targets synaptic NMDAR. An agonist of protease activated receptor 1 (PAR1) was used to induce astrocytic Ca2+ increase and glutamate release. Firstly, we found that activation of PAR1 and subsequent release of glutamate from astrocyte does not alone increase the frequency of mEPSCs. Secondly, we found that mEPSC rise time is variable depending on the different electrotonic distances from the somatic recording site to the synaptic region where each mEPSC occurs. Two subgroups of mEPSC from CA1 pyramidal neuron by rise time were selected and analyzed. One group is fast rising mEPSCs with a rise time of 1 ~ 5 ms, representing synaptic activities arising from proximal dendrites. The other group is slowly rising mEPSCs with a rise time of 5 ~ 10 ms, representing synaptic events arising from glutamate release at synapses located in the distal dendrites. We used cell-type specific Best1 gene silencing system by Cre-loxP cleavage to dissociate the effect of neuronal and astrocytic Best1. Astrocytic Best1-mediated glutamate release by PAR1 activation did not affect decay kinetics, frequency, and amplitude of fast rising mEPSC. In contrast, PAR1 activation resulted in an NMDA receptor component to be present on slowly rising mEPSC, but did not alter frequency or amplitude. Conclusions Our results indicate that astrocytic glutamate via Best1 channel targets and activates synaptic NMDARs.
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