• Bulletin of the Korean Mathematical Society
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• v.60 no.4
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• pp.905-913
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• 2023

Suppose that M is a strictly convex hypersurface in the (n + 1)-dimensional Euclidean space 𝔼ⁿ⁺¹ with the origin o in its convex side and with the outward unit normal N. For a fixed point p ∈ M and a positive constant t, we put 𝚽_t the hyperplane parallel to the tangent hyperplane 𝚽 at p and passing through the point q = p - tN(p). We consider the region cut from M by the parallel hyperplane 𝚽_t, and denote by I_p(t) the (n + 1)-dimensional volume of the convex hull of the region and the origin o. Then Schneider's characterization theorem for ellipsoids states that among centrally symmetric, strictly convex and closed surfaces in the 3-dimensional Euclidean space 𝔼³, the ellipsoids are the only ones satisfying I_p(t) = 𝜙(p)t, where 𝜙 is a function defined on M. Recently, the characterization theorem was extended to centrally symmetric, strictly convex and closed hypersurfaces in 𝔼ⁿ⁺¹ satisfying for a constant 𝛽, I_p(t) = 𝜙(p)t^𝛽. In this paper, we study the volume I_p(t) of a strictly convex and complete hypersurface in 𝔼ⁿ⁺¹ with the origin o in its convex side. As a result, first of all we extend the characterization theorem to strictly convex and closed (not necessarily centrally symmetric) hypersurfaces in 𝔼ⁿ⁺¹ satisfying I_p(t) = 𝜙(p)t^𝛽. After that we generalize the characterization theorem to strictly convex and complete (not necessarily closed) hypersurfaces in 𝔼ⁿ⁺¹ satisfying I_p(t) = 𝜙(p)t^𝛽.

• Investigative Magnetic Resonance Imaging
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• v.19 no.4
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• pp.218-223
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• 2015

Purpose: To investigate whether volumetric analysis based on T2WI and contrast-enhanced (CE) T1WI can distinguish between isocitrate dehydrogenase-1 mutation-positive ($IDH1^P$) and -negative ($IDH1^N$) glioblastomas (GBMs). Materials and Methods: We retrospectively enrolled 109 patients with histopathologically proven GBMs after surgery or stereotactic biopsy and preoperative MR imaging. We measured the whole-tumor volume in each patient using a semiautomatic segmentation method based on both T2WI and CE T1WI. We compared the tumor volumes between $IDH1^P$ (n = 12) and $IDH1^N$ (n = 97) GBMs using an unpaired t-test. In addition, we performed receiver operating characteristic (ROC) analysis for the differentiation of $IDH1^P$ and $IDH1^N$ GBMs using the tumor volumes based on T2WI and CE T1WI. Results: The mean tumor volume based on T2WI was larger for $IDH1^P$ GBMs than $IDH1^N$ GBMs ($108.8{\pm}68.1$ and $59.3{\pm}37.3mm^3$, respectively, P = 0.0002). In addition, $IDH1^P$ GBMs had a larger tumor volume on CE T1WI than did $IDH1^N$ tumors ($49.00{\pm}40.14$ and $22.53{\pm}17.51mm^3$, respectively, P < 0.0001). ROC analysis revealed that the tumor volume based on T2WI could distinguish $IDH1^P$ from $IDH1^N$ with a cutoff value of 90.25 (P < 0.05): 7 of 12 $IDH1^P$ (58.3%) and 79 of 97 $IDH1^N$ (81.4%). Conclusion: Volumetric analysis of T2WI and CE T1WI could enable $IDH1^P$ GBMs to be distinguished from $IDH1^N$ GBMs. We assumed that secondary GBMs with $IDH1^P$ underwent stepwise progression and were more infiltrative than those with $IDH1^N$, which might have resulted in the differences in tumor volume.

• Journal of Chest Surgery
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• v.38 no.6 s.251
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• pp.421-427
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• 2005

Complete surgical resection is the most effective treatment for pT1/2N1 non-small cell lung cancer, however 5 year survival rate of these patients is about $40\%$ and the major cause of death is recurrent disease. We intended to clarify the risk factors of recurrence in completely resected pT1/2N1 non-small cell lung cancer. Material and Method: From Jan. f990 to Jul. 2003, total of 117 patients were operated for pT1/2N1 non-small cell lung cancer. The risk of recurrence according to patients characteristics, histopathologic findings, type of resection, pattern of lymph node metastasis, postoperative adjuvant treatment were evaluated retrospectively. Result: Mean age of patients was 59.3 years. There were 14 patients with T1N1 and 103 patients with T2N1 disease. Median follow-up time was 27.5 months and overall 5 year suwival rate was $41.3\%$. 5 year freedom-from recurrence rate was $54.1\%$. Recurrence was observed in $44 (37.6\%)$ patients and distant recurrence developed in 40 patients. 5 year survival rate of patients with recurence was $3.3\%$, which was significantly lower than patients without recurrence $(61.3\%,\;p=0.000).$ In multi-variate analysis of risk factors for freedom-from recurrence rate, multi-station N1 $(hazard\;ratio=1.997,\;p=0.047)$ was a poor prognostic factor. Conclusion: Multi-station N1 is the risk factor for recurrence in completely resected pT1/2N1 non-small cell lung cancer.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.119-128
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• 2003

The two experiments in this study compared litter nitrogen (N) contents after broiler chicks were raised for 42 days. Experiment I compared litter treated with aluminum sulfate (alum) [Al$_2$(SO$_4$)$_3$ㆍ14$H_2O$] (T$_1$) with nontreated litter (T$_2$) when the broiler chicks were fed the same levels of dietary protein (23% for 0∼3 weeks, 21% for 4∼6 weeks) Experiment 2 compared the alum treated litters of broiler chicks fed high protein diets (T$_3$) having 20.4% protein for 0∼3 weeks and 19.3% for 4∼6 weeks, with lower protein diets (T$_4$) having protein levels of 18.0% for 0∼3 weeks and 17.0% for 4 6 weeks. Each treatment had four replicate cages. As shown in Table 1, T$_1$ had a significantly (P<0.0l) lower pH and significantly (P<0.05) higher total N (TN), NH$_4$-N and inorganic N (IN) than T$_2$. T$_1$ and T$_2$ had similar moisture, organic carbon (OC), NO$_3$-N and organic N (ON). Alum treatment increased available N (AN) significantly (P<0.05) from 13.75$\pm$0.0l mg/g to 14.90$\pm$0.01 mg/g and predicted available N (PAN) significantly (P<0.05) from 15.00$\pm$0.0l to 16.50$\pm$0.02. The C : N ratios were 18.84$\pm$0.40 (T$_1$) and 19.46$\pm$0.10 (T$_2$) while the C : ON ratios were 28.49$\pm$1.15 (T$_1$) and 28.34$\pm$0.20 (T$_2$) although C : N ratios or C : ON ratios did not show any difference between T$_1$ and T$_2$. In Table 2, T$_3$ had significantly (P<0.05) higher moisture, TN, NH$_4$-N, ON and IN than T$_4$, while the pH, OC and NO$_3$-N were similar in both groups. The AN of T$_3$ increased significantly (P<0.05) from 10.99$\pm$0.0l mg/g to 12.98$\pm$0.03 mg/g, while the PAN increased significantly (P<0.05) from 12.39$\pm$0.10 mg/g (T$_4$) to 14.68$\pm$ 0.30 mg/g (T$_3$). The C : N ratios increased significantly (P<0.0l) from 20.07$\pm$0.20 (T$_3$) to 24.40$\pm$0.10 (T$_3$). The C : ON ratios also increased significantly (P<0.0l) from 28.99$\pm$1.15 (T$_3$) to 35.51$\pm$0.20 (T$_4$). These current research results show increased AN contents and PAN contents in alum treated litter or with increased CP levels regardless of alum treatment. However, none of the litters in this study could initially increase mineralization.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.524-524
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• 2016

본 연구에서는 홍천 자운지구 고랭지 농업지역을 대상으로 장기간의 유역조사와 하천 모니터링을 통해 관측된 축척 데이터를 이용하여 비점오염저감 효과를 정량화하고 추후 모니터링 자료로서 탁수와 비점오염원 저감시설의 저감효과와 비점오염원의 효율적인 관리를 위한 기초자료를 제공하고자 하였다. 모니터링 결과 소양호 유역의 오염부하(1차 강우사상) 중 홍천군 자운지구의 유역단위 비점오염 저감효과의 분석에는 강우량과 단위면적당 오염부하를 이용하였으며, 자운천은 SS 5,396,761 kg, COD 82,261 kg, BOD 57,329 kg, T-N 68,711 kg, T-P 3,091 kg이었으며, 오염부하(2차 강우사상)는 SS 320,293 kg, COD 34,588 kg, BOD 22,350 kg, T-N 48,954 kg, T-P 640 kg으로 나타났다. 또한 소양호 유역의 EMC(1차 강우사상) 중 자운천은 SS 829.9 mg/L, COD 12.7 mg/L, BOD 8.8 mg/L, T-N 10.567 mg/L, T-P 0.475 mg/L 이었으며, EMC(2차 강우사상)는 SS 68.6 mg/L, COD 7.4 mg/L, BOD 4.8 mg/L, T-N 10.487 mg/L, T-P 0.137 mg/L로 나타났다. 소양호 유역의 단위면적당 오염부하(1차 강우사상) 중 자운천은 SS 402.0 kg/ha/event, COD 6.1 kg/ha/event, BOD 4.3 kg/ha/event, T-N 5.118 kg/ha/event, T-P 0.230 kg/ha/event 이었으며, 오염부하(2차 강우사상)는 SS 23.9 kg/ha/event, COD 2.6 kg/ha/event, BOD 1.7 kg/ha/event, T-N 3.646 kg/ha/event, T-P 0.048 kg/ha/event로 나타났다. 오염부하에서는 1차 강우에 비해 2차 강우에서는 SS 5,076,468 mg/L, COD 47,673 mg/L, BOD 34,979 mg/L, T-N 19,757 mg/L, T-P 2451 mg/L로 1차 강우사상에 비해 오염부하가 낮은 것으로 나타났다. 또한 EMC에서는 1차 강우에 비해 2차 강우에서는 SS 761.3 mg/L, COD 5.3 mg/L, BOD 4.0 mg/L, T-N 0.080 mg/L, T-P 0.338 mg/L로 1차 강우사상에 비해 EMC가 저감되었다. 단위면적당 오염부하는 1차 강우에 비해 2차 강우에서는 SS 378.1 mg/L, COD 3.5 mg/L, BOD 2.6 mg/L, T-N 1.472 mg/L, T-P 0.182 mg/L로 1차 강우사상에 비해 EMC가 저감되었다. 강우량과 강우강도 그리고 영농활동의 시기에 따른 EMC와 단위면적당 오염부하는 큰 차이를 보였으며, 예년에 비해 적은 강수량으로 인해 탁수와 비점오염부하의 배출이 상대적으로 적었던 것으로 판단된다. 소양호 유역과 같은 넓은 유역에서 시행되는 비점오염원의 저감연구는 오랜 시간 동안 자료를 축적해야 유의미한 평가가 이루어질 수 있으므로 장기적이고 지속적인 모니터링을 통한 유량 데이터 자료구축과 수질분석뿐만 아니라, 발생되는 비점오염 물질의 관리를 위한 체계적인 연구가 지속되어야하며, 아울러 농민의 인식도 변화 등을 포함하는 많은 인자들을 정밀히 조사하고 다각도로 분석하여 저감효과에 대한 지속적인 연구가 필요하다.

• Journal of Environmental Science International
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• v.31 no.11
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• pp.989-992
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• 2022

This study was conducted to investigate the efficacy of larval stages of three species, namely, Tenebrio molitor, Protaetia brevitarsis seulensis, and Ptecticus tenebrifer larvae, in degrading poultry manure, specially, broiler and duck manure. The survival rates of larvae were also noted. For the experiment, T. molitor (n=300), P. brevitarsis seulensis (n=60), and P. tenebrifer (n=300) hatched larvae were randomly divided into six groups with three replicates. The degaradation efficacy tests were then performed for 30 days in a laboratory. The test groups were as follows: T1, 110 g broiler manure + T. molitor larvae (n=50); T2, 110 g duck manure + T. molitor larvae (n=50); T3, 125 g broiler manure + P. brevitarsis seulensis larvae (n=10); T4, 125 g duck manure + P. brevitarsis seulensis larvae (n=10); T5, 105 g broiler manure + P. tenebrifer larvae (n=50); and T6, 105 g duck manure + P. tenebrifer larvae (n=50). The groups showed significant efficacy in degrading broiler and duck manure (p<0.05). The highest survival rates were recorded for T. molitor larvae in both manure types [T1 (92.67%) and T2 (50%)], followed by P. brevitarsis seulensis larvae (T4, 40%) and P. tenebrifer larvae (T6, 14.67%) in duck manure. Next, the survival rates of P. brevitarsis seulensis (T3) and Ptecticus tenebrifer larvae (T5) in broiler manure were 0%. In conclusion, these results point to the feasibility of using insect larvae to degrade broiler and duck manure.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.400-407
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• 2011

To evaluate the aquatic ecological characteristics in Sinpyongcheon constructed wetlands for treating nonpoint source pollution, the removal rates of nutrients in water, the total amounts of T-N and T-P uptakes by water plants, and chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD, COD, SS, T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were 14%, 6%, 18%, 24%, and 10%, respectively. The maximum amount of T-N uptake by water plants in August was $813mg\;plant^{-1}$ for Phragmites communis TRIV in $2^{nd}$ bed, $1,172mg\;plant^{-1}$ for Typha orientalis PRESL in $3^{rd}$ bed, respectively. The maximum amount of T-P uptake by water plants in August was $247mg\;plant^{-1}$ for Phragmites communis TRIV in $2^{nd}$ bed, $359mg\;plant^{-1}$ for Typha orientalis PRESL in $3^{rd}$ bed, respectively. Organic matter, T-N, and T-P contents in sediments were high in the order of $1^{st}$ bed > $2^{nd}$ bed > $3^{rd}$ bed. Microbial biomass C/N/P ratios in sediments in $1^{st}$, $2^{nd}$, and $3^{rd}$ were 78~110/3~6/1, 73~204/1~6/1, and 106~169/1~6/1, respectively.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.3
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• pp.427-431
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• 2014

In this paper, we show that groups of order $2^npq$, where p, q are primes of the from $p=2^n-1$, $q=2^{n-1}+p$ with $n{\geq}3$, are not simple and groups of order $2^npq^t$ for $t{\geq}2$, where p, q are odd primes of the form $p=2^m-1$, $q=2^n-1$ with m < n, are not simple.

• East Asian mathematical journal
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• v.35 no.3
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• pp.285-288
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• 2019

Let $F_n$, $n{\in}{\mathbb{N}}$ be the n - th Fibonacci number, and let (p, q) be one of ordered pairs ($F_{n+2}$, $F_n$) or ($F_{n+1}$, $F_n$). Then we show that the multiplicative inverse of q mod p as well as that of p mod q are again Fibonacci numbers. For proof of our claim we make use of well-known Cassini, Catlan and dOcagne identities. As an application, we determine the number $N_{p,q}$ of nonzero term of a polynomial ${\Delta}_{p,q}(t)=\frac{(t^{pq}-1)(t-1)}{(t^p-1)(t^q-1)}$ through the Carlitz's formula.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.4
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• pp.54-61
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• 1999

SBR process used to evaluate the removal of organics, nitrogen and phosphorus on the basis of a report of research on a precedence at various operation cycle and condition change. Effluent concentration of COD were 50mg/l, 50mg/l, 90mg/l respectively, The removal rates of COD were nearly over 95% at Run 1, 2 and 4. But at Run 3, Effluent concentration of COD was 255.0mg/l, The removal rate of COD was 87% at Run 3. As Oxic/Anoxic rate was fixed and operating cycle of Oxic/Anoxic was changed, the removal rates of T-N were 74.7%, 46.9%, 28.5%, 63.3% respectively at Run 1~4. The case of Run 1 was best result. The removal rates of T-P was appeared in proportion to T-N removal rates and rest of $NO_2-N$. The removal rates of T-P were 51.2%, 35.5%, 41.5%, 51.9% respectively. The removal rates of COD, T-N, T-P were influenced on the change of SBR operation cycle. As organic loading rate was $1.43kgCOD/m^3day$ and C/N ratio was 3.0, operation cycle of Run 1 was best condition of T-N removal rates and T-P removal.