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Current Sensorless ZPA Frequency Tracking Control of IPT System with LCCL-S Topology
Jongeun Byun,Won-Jin Son,Jae Han Lee,Sangjoon Ann,Byoung Kuk Lee 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
Inductive power transfer (IPT) systems for electric vehicles (EVs) should apply zero-phase angle (ZPA) frequency control methods for achieving low VA rating and high efficiency. In order to apply ZPA frequency control, current sensors are needed in previous studies. However, these sensors have several problems using for ZPA frequency control such as switching noise, degrading control performance, control complexity, and so on. Therefore, this paper proposes the simpler control method without current sensor for ZPA frequency tracking with LCCL-S topology of IPT systems. The optimal design point is also deducted to apply the proposed control. A simulation and an experiment of 3.3-kW IPT system are performed to verify the proposed control.
Is early laser treatment necessary for the children with scar?
( Jongeun Lee ),( Hyun Jeong Byun ),( Chan Seong Park ),( Youngkyoung Lim ),( Jong-hee Lee ) 대한피부과학회 2018 대한피부과학회 학술발표대회집 Vol.70 No.2
Background: Most of parents are eager to manage their children’ scars as early as possible. However, patients themselves generally show bad compliances during procedures. Younger patients tend to develop hypertrophic scar easily compared with older ones and even though scars do not show hypertrophic changes, scar widening can happen as they grow older. Objectives: We aimed to evaluate whether laser treatment of scars in young patients is necessary in spite of toughness during treatment. Methods: A retrospective study was conducted on scar patients under age 17 who visited Samsung Medical Center from September 2013 to June 2018. Patients who visited the clinic before the initiation of scar maturation received laser therapy while those came in the midst of or after the scar maturation only received topical treatment. Stony Brook Scar Evaluation Scale (SBSES) was used for assessment of scar. Results: The mean time intervals between injury/suture and initial visit to clinic were 23.1 days for laser group while 89.4 days for topical group. Average SBSES score at first visit was higher for topical group (2.83 vs 1.78 points, p < 0.001). After subsequent treatments, average SBSES score was similar between the two groups (4.39 vs 4.44 points, p > 0.05) and laser group showed greater improvement in average SBSES score (1.56 vs 2.67, p < 0.002). Conclusion: When a patient in young age visits early or before scar maturation, laser intervention can be a desirable treatment option.
( Jongeun Lee ),( Hyun Jeong Byun ),( Chan Seong Park ),( Youngkyoung Lim ),( Sewon Park ),( Ji-hye Park ),( Dong-yoon Lee ) 대한피부과학회 2018 대한피부과학회 학술발표대회집 Vol.70 No.2
Background: Nail matric nevus (NMN) is a benign melanocytic proliferative lesion that arises from the nail matrix. It has been a challenge to differentiate NMN from malignant lesions such as subungual melanoma (SUM), especially in children as their NMNs may present and mimic clinical features of SUM such as Hutchinson’s sign, nail dystrophy, and prominent globules in dermoscopy. Objectives: We studied whether the presence of longitudinal brush pigmentation (LBP) on hyponychium can be a helpful dermoscopic feature in diagnosing nail matrix nevus. Methods: A retrospective study was conducted on patients under age 18, who showed LBP on hyponychium at Samsung Medical Center from 2014 to 2018. Results: There were total 19 patients who showed LBP on hyponychium with mean age of 17 months. Eight out of 19 patients had nail dystrophy and mean width of melanonychia was around 60.5%. Under dermoscopic examination, 11 patients showed irregular pattern while globules were observed in 6 cases. Nail clipping biopsy was done for 12 patients and all revealed melanin pigments in the nail plates. Total 6 patients received 3mm punch biopsy at Hutchinson’s sign with LBP. Melanocytic nests were clearly seen in 4 patients while 2 cases showed increased basal pigmentation without atypia; none showed atypical histologic findings suggestive of SUM. Conclusion: We suggest that longitudinal brush pigmentation may serve as an important clinical feature that can guide to diagnose NMN over SUM in children.
( Jongeun Lee ),( Dongmin Shin ),( Donghwi Jang ),( Hyun Jeong Byun ),( Se-jin Oh ),( Hyun Je Kim ),( Ji-hye Park ),( Jong-hee Lee ),( Won Park ) 대한피부과학회 2020 대한피부과학회 학술발표대회집 Vol.72 No.1
Background: Radiotherapy (RT) may accompany acute skin reactions from mild erythema to confluent moist desquamation and ulceration. Objectives: We aimed to evaluate the effectiveness of PBMT in the prevention of acute radiodermatitis in breast cancer patients undergoing RT. Materials and methods: This study was a single-blinded prospective trial. The subjects were divided into three groups -control group (PBMT not done, n=10), group 1 (633nm, n=16), and group 2 (830nm, n=16). PBMT was performed 3 times a week from the 4th week of RT up to a week after the end of RT. Common Terminology Criteria for Adverse Events grade and skin measurements (melanin, erythema, moisture, and sebum content index) were evaluated at four different time points - before RT (V0), after 3 weeks of RT (V1), after the end of RT (V2), and 1 month after completion of RT (V3). Results: In the control group, 7 patients (77.8%) developed grade 1 reactions and 2 (22.2%) patients grade 0 at V3. In group 2, all patients presented grade 0 at V3. Group 1 had less melanin difference between irradiated and non-irradiated breasts from baseline compared to the control group at V3 (p=0.0004). Both group 1 and 2 showed greater increased level of moisture index from baseline at V3 than the control group. For sebum index, control group showed lower sebum level at V2 compared to group 2 and at V3 compared to group 1 and 2. Conclusion: Both wavelengths (633nm and 830nm) of PBMT are effective for the prevention of acute radiodermatitis.
A case of cowden syndrome with multi-systemic tumors and thyroid cancer
( Jongeun Lee ),( Hyun Jeong Byun ),( Chan Seong Park ),( Youngkyoung Lim ),( Ji-hye Park ),( Jong Hee Lee ),( Dong-youn Lee ),( Joo-heung Lee ),( Jun-mo Yang ) 대한피부과학회 2019 대한피부과학회 학술발표대회집 Vol.71 No.1
Cowden syndrome is caused by mutation in phosphatase and tensin homolog (PTEN) gene, belonging to PTEN hamartoma tumor syndrome. A 21-year-old female presented with small papules on palms and neck. In addition, there were solitary papules under the nose and the upper lip and skin tags on both axilla. Her past medical history included intramuscular arteriovenous malformation versus hemangioma on right lower leg, cyst in the right ovary, multiple follicles in the left ovary, fibroadenoma in the left breast, and phyllodes tumor and intraductal papilloma in the right breast. Moreover, additional mass in thyroid turned out to be a papillary thyroid carcinoma. The mutation analysis for PTEN hamartoma syndrome confirmed pathogenic variant in the PTEN gene. A 3mm-punch biopsy on the left palm revealed regular orthokeratosis and hyperkeratosis consistent with palmoplantar keratosis. During the follow up visits, the patient developed hematochezia due to numerous hyperplastic and lymphoid polyps in stomach through rectum. Cowden syndrome possesses increased risk of developing malignancies including breast, thyroid, and colorectal cancers. Therefore it is important for dermatologists to recognize symptoms of the possible multi-systemic tumors in these patients. Herein, we present a case of Cowden syndrome with multi-systemic tumors and thyroid cancer.
A case of follicular mucinosis in a child at unusual location
( Jongeun Lee ),( Hyun Jeong Byun ),( Chan Seong Park ),( Youngkyoung Lim ),( Ji-hye Park ),( Jong Hee Lee ),( Dong-youn Lee ),( Joo-heung Lee ),( Jun-mo Yang ) 대한피부과학회 2019 대한피부과학회 학술발표대회집 Vol.71 No.1
Follicular mucinosis (FM) is usually presented as welldemarcated erythematous or skin-colored patches with follicular papules at head or neck. It is a rare entity in children. A healthy 4-year-old boy presented with a 1-month history of an erythematous patch at left dorsum of nose. The patch was rather uneven because of follicular papules and firm on palpation. The pathologic findings showed deposition of blue amorphous material in sebaceous gland with lymphocytic infiltration, suggesting inflammation of sebaceous gland without histopathologic features of mycosis fungoides such as epidermotropism of lymphocytes or lymphoid atypia. The lesion was completely healed after 6 weeks of topical steroid (0.25% prednicarbate). Although it has been described to follow benign courses in children, close follow up is warranted as it is difficult to distinguish idiopathic FM and lymphoma-associated FM. In English literature published so far, head accounted for around 80% in the solitary FM cases. Forehead and chin were the most frequently involved location while FM involving nose was reported only twice, each in multiple and solitary cases. Herein, we report a case of FM in a child at nose treated with topical steroid.
Minkook Kim,Jongeun Byun,Byoung Kuk Lee 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.3
In this paper, performance of rectangular shaped magnetic power pads for inductive power transfer (IPT) system according to ferrite structure is analyzed. In order to evaluate the influences of ferrite structure, six cases of magnetic power pads are proposed. Self-inductance, coupling coefficient, quality factor, and coil to coil efficiency are compared as the displacement increases in the direction of x or y axis. For accurate estimation, finite element method (FEM) simulation is used and loss components of the power pads are numerically calculated and considered. Through the simulation and measured results, effectiveness of protrusive and enveloping ferrite structure is identified.
( Hyun Jeong Byun ),( Donghwi Jang ),( Jongeun Lee ),( Se Jin Oh ),( Youngkyoung Lim ),( Ji-hye Park ),( Jong Hee Lee ),( Dong-youn Lee ) 대한피부과학회 2021 Annals of Dermatology Vol.33 No.3
A capillary hemangioma is a vascular tumor with small capillary sized vascular channel. Multiple capillary hemangioma in relation with drugs have been rarely reported. Here in, we report a case of multiple capillary hemangioma in patient diagnosed with chronic myeloid leukemia who received tyrosine kinase inhibitors (TKIs). Histopathological findings have shown capillary proliferation in the upper dermis, which is consistent with capillary hemangioma. Since TKIs can paradoxically activate the MEK/ERK pathway which is required for angiogenesis, we presumed that the lesions as the cutaneous side effects of TKIs. (Ann Dermatol 33(3) 278∼280, 2021)