Pyongyang University of Science and Technology

In energy-constrained wireless sensor networks (WSNs) composed of sensor nodes (SNs) characterized by multi-criteria contradictory with each other, it is still one of the challenges to be solved to figure out how to combine multi-criteria with each other and how to use an intelligent optimization (IO) algorithm for developing an optimal cluster-based routing protocol. In this article, we overture a new routing protocol based on uneven cluster using the hybrid FCNP-VWA-TOPSIS (FVT) and an improved max-min ant colony optimization (ACO). This scheme uses the hybrid FVT to perform the clustering, and uses an improved max-min ACO to configure a routing tree for the relay transmission of sensed data. The extensive simulation experiments have been carried out to show that the proposed scheme greatly prolongs the network lifetime (NL) by achieving an energy consumption balance superior to the previous schemes.

Statement of the problem. Winter concrete construction requires antifreeze admixtures that prevent freezing while maintaining strength development. Conventional nitrite- and chloride-based antifreezes face high costs and corrosion concerns. Industrial by-products like cement kiln dust (CKD) offer potential for sustainable antifreeze production, yet their application in nitrate-sulfate composite systems remains unexplored. A CKD-based nitrate-sulfate composite antifreeze was synthesized by reacting CKD-lime suspension with mixed HNO₃:H₂SO₄ (1:1 ratio) to yield a 40 % solids suspension containing KNO₃, Ca(NO₃)₂, K₂SO₄, CaSO₄, and 0.05 % triethanolamine. Performance was evaluated at three temperature ranges (–4 to –6 °C, –9 to –11 °C, and –14 to –16 °C)against four commercial antifreeze formulations through standardized testing of compressive strength, setting time, water absorption, frost resistance, and outdoor durability. Economic analysis compared production costs with commercial alternatives. Results. At –9 to –11°C, 5—6 % dosage prevented freezing and achieved 28-day strengths of 6.2 MPa, comparable to commercial calcium nitrate-based antifreeze (6.0 MPa) and superior to potassium carbonate-based (5.7 MPa) and calcium chloride-based (5.9 MPa) products. Setting time decreased by 50 %, water absorption reduced by 15 %, and freeze-thaw resistance improved from 28 to 46—47 cycles. Production costs of $95—105 per metric ton represent 78—82 % savings compared to commercial antifreezes ($420—480 per ton), translating to $735 savings per 100 m³ concrete. Conclusions. The CKD-based composite antifreeze demonstrates comparable or superior performance to commercial products while achieving substantial cost reduction through industrial waste valorization. Recommended dosages are 3—5 %, 5—7 %, and 8—10 % by cement weight for –4, –10, and –15 °C environments, respectively.

The main mission of the intelligent tutoring system is to estimate and predict the students’ learning status accurately and to generate a learning path that is inherent to the students. There are many learning state estimation and prediction methods, and there are also many methods to generate learning paths using the results. We propose a method to predict the learning state of a student and generate a learning path using the Hidden Markov Model, a probabilistic reasoning over time. We propose and illustrate in detail how to formalize the Hidden Markov Model using an extended knowledge graph for learning state prediction, how to collect the evidence variable values of the Hidden Markov Model in intelligent tutoring systems, how to predict the learning state using smoothing algorithms, and how to generate the stochastic learning path. The experiment was conducted to compare students using an intelligent tutoring system with those who did not. In addition, a comparison experiment of a method using Hidden Markov model with a multi-dimensional linear prediction model such as PFM and AFM was also carried out. The results showed that the average performance of students using the intelligent tutoring system was much higher than that of students without the intelligent tutoring system. In addition, the experimental results showed that the average performance of students using Hidden Markov models was higher than that of students using other models.

Background and Aim: Osteoporosis is an important type of metabolic bone disease in chronic cholangiogenic liver disease, with an incidence of up to maximum 72%. Osteoporosis and osteomalacia in patients with chronic liver disease are collectively referred to as "hepatic osteodystrophy," which is commonly found in patients with intestinal malabsorption and progressive primary biliary cirrhosis. To deal with the induction of osteoporosis by chronic cholestasis, we aimed to investigate the following: The aim of the study was to investigate the effect of iron intake on chronic cholestatic osteoporosis by surgical CBD partial ligation. Methods: Forty rats including weanling male rats weighing 70-80 g and adult male rats weighing 150-160 g were used. First, the rats were anesthetized with intraperitoneal ketamine injection, and then the CBD (Common Bile Duct) was exposed by surgical procedures, complete and partial ligation was performed, and then the abdomen was closed. Partial ligation was performed by ligating different thicknesses of the suture needles with the common bile duct and then removing the suture needle. In the case of using suture needle 5-0, 85-90% of the common bile duct is considered to be obstructed and 75-80% for 4-0. After ligation of the common bile duct, naturally proceeding rats were included as contrast group and rats receiving oral administration of 6 mg/ kg/day of folate iron were included as experimental group. After 8 weeks, liver function tests (ALT, AST, ZTT) and histopathological observation of the femur (H-E stained samples) were performed in the contrast and experimental groups, respectively. The significance test for viability and prevalence of osteoporosis following CBD ligation was performed by using the chi-square test, and the significance test for liver function test values was performed by using the t-test. Results: Experimental osteoporosis is induced at 8 weeks after surgical CBD partial ligation (85-90% occlusion). Conclusion: Iron intake significantly suppressed the development of osteoporosis by chronic cholestasis.

Purpose: Our purpose is to set up the new criteria for initiating NOEF(non-oral enteral feeding) safely in acute pancreatitis patients by analyzing several univariate indices and multivariate clinical scoring systems measured in the early days of NOEF. Methods: We involved moderately severe and severe acute pancreatitis patients who received NOEF treatment. We made a univariate and multivariate analysis of all the demographical, clinical, laboratory, radiological indices and clinical scores before NOEF, to find out the independent evaluation factors of paralytic ileus during NOEF. By analyzing ROC(receiver operating characteristics) curve, optimal cut-off points of selected independent risk factors were defined. We determined the ranges below the cut-off points as the safe ranges out of paralytic ileus during NOEF. Results: A total of 136 patients was involved in our study. By the univariate analysis, abdominal pain, respiratory rate, body temperature, rebound tender on physical examination, band neutrophil count, SIRS(systemic inflammatory response syndrome) score, PASS(pancreatitis activity scoring system), BISAP(bedside index of severity in acute pancreatitis), Balthazar score were associated with occurrence of paralytic ileus during NOEF(P<0.05). By the multivariate analysis, respiratory rate and PASS were selected as the independent risk factors of paralytic ileus during NOEF(P<0.05). Areas under ROC curves(AUROCs) of respiratory rate and PASS in predicting paralytic ileus were 0.873(0.777-0.970), 0.897(0.795-0.999), respectively. The optimal cut-off points of highest odds ratios(OR) and negative predictive values(NPV) in predicting paralytic ileus after NOEF were respiratory rate≧25bpm and PASS≧120, respectively. Conclusion: Safe range for NOEF during acute pancreatitis treatment is PASS<120 or respiratory rate<25bpm.

To describe the structural phase transitions P42/mnm(R) ↔ P21/c(M1) ↔ P1(T) ↔ C2/m(M2) observed experimentally in VO2 and its solid solutions, the two-component order parameter model is newly proposed. We identify the space groups of 102 ordered phases induced by the 36 irreducible representations of the ten star channel groups related to six Lifshitz stars in the Brillouin zone of space group P42/mnm, and show that these are characterized by the invariant characteristic quantities of four image groups (L groups). In particular, it is shown that the two-component order parameter model transformed according to the two-dimensional irreducible representation T2 of star channel group P42/mnm[k16(1)] is far more effective than the four-component one for describing the phase transitions observed experimentally in VO2 and its solid solutions. The structurally stable Landau potential models with one to five varying parameters and invariant under the L28(4mm) group are suggested for the phenomenological studies based on the two-component order parameter model. By using the eighth-order Landau potential model with three varying parameters, the coefficient phase diagram and the temperature-concentration phase diagram are theoretically constructed, which are in good agreement with the experimental data of V1-xAlxO2.

Background and Aim: Hyperemesis Gravidarum (HG) is a common early pregnancy syndrome that usually occurs around 4 to 5 weeks of gestation, which is initiated with sour throw-up from the empty stomach in the morning, disgusting to smell, change of appetite and exacerbated with severe nausea, frequent vomiting and inability to eat, which gives side effects on quality of life and health of the pregnant woman. Generally, GH causes malnuturition and dehydration, if it is not treated in time, some complications such as Wernick’s encephalopathy and low-weight neonate birth can be caused. Now antiemetics involving antihistamine, phenothiazine, Vitamin B6, metoclopramide and ondansetrone are used for HG and steroids are recommended for the last choice but they are limited in use from the fear that chemical medicine is a risk to pregnancy. To identify the effectiveness of traditional medicine, Ijin Granules on PUQE score and the change of intake in pregnant women with hyperemesis granvidarum who complaints of severe nausea and vomiting. Methods: Between Jaunary 2024 and December 2024, 60 cases of HG were enrolled in the study at Pyongyang Maternity Hospital, Pyongyang, Democratic People’s Republic of Korea. The patients were randomly divided into study group (30 cases) and control group (30 cases). The control group was given only fluid replacement therapy and the study group orally given Ijin Granules (5 g) 3 times daily with the fluid therapy for 7 days. The effectiveness was analyzed between the two groups with PUQE score, QOL score, SDS score and the amount of intake. Results: After 7 days of the treatment the PUQE and SDS scores in the study group were lower as compare to the control group, QOL score and intake in the study group were higher as compare to the control group. The total effective rate of treatment in the study group (93.33%) was significantly greater than that in the control group (66.67%). Conclusion: Ijin Granules had a significant effect on nausea and vomiting, improved QoL and intake in pregnant women with HG, when combined with fluid replacement therapy, it promotes the healthy pregnancy.

Osteoporosis is an important type of metabolic bone disease in chronic cholangiogenic liver disease, with an incidence of up to maximum 72%. Osteoporosis and osteomalacia in patients with chronic liver disease are collectively referred to as "hepatic osteodystrophy," which is commonly found in patients with intestinal malabsorption and progressive primary biliary cirrhosis. To deal with the induction of osteoporosis by chronic cholestasis, we aimed to investigate the following: The aim of the study was to investigate the effect of iron intake on chronic cholestatic osteoporosis by surgical CBD partial ligation. Forty rats including weanling male rats weighing 70-80g and adult male rats weighing 150-160g were used. First, the rats were anesthetized with intraperitoneal ketamine injection, and then the CBD (common bile duct) was exposed by surgical procedures, complete and partial ligation was performed, and then the abdomen was closed. Partial ligation was performed by ligating different thicknesses of the suture needles with the common bile duct and then removing the suture needle. In the case of using suture needle 5-0, 85-90% of the common bile duct is considered to be obstructed and 75-80% for 4-0. After ligation of the common bile duct, naturally proceeding rats were included as contrast group and rats receiving oral administration of 6 mg/kg/day of folate iron were included as experimental group. After 8 weeks, liver function tests (ALT, AST, ZTT) and histopathological observation of the femur (H-E stained samples) were performed in the contrast and experimental groups, respectively. The significance test for viability and prevalence of osteoporosis following CBD ligation was performed by using the chi-square test, and the significance test for liver function test values was performed by using the t-test. Experimental osteoporosis is induced at 8 weeks after surgical CBD partial ligation (85-90% occlusion). Iron intake significantly suppressed the development of osteoporosis by chronic cholestasis.