• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.485-488
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• 2006

In order to investigate the possibility of waste mushroom logs as biomass resource chemical and physical characteristics of normal woods and waste mushroom logs such as crystallinity value, energy consumption, total sugar yield after hydrolysis chemical compounds and molecular weight distribution after acid hydrolysis, were examined. In the results, crystallinity of waste mushroom logs which were three year passed after the inoculation was decreased drastically from 49% to 33% during the cultivation. Lignin contents as chemical compounds of normal woods and waste mushroom logs were 21.07% and 18.78%, respectively. By the results of measurement of energy consumption, the size reduction of normal woods required a significantly higher energy than that of waste mushroom logs. In the hydrolysis, total sugar yield by enzyme and acid hydrolysis were high in waste mushroom logs(53% 57.5%) than in normal woods(42.9%, 47.17%). According to the molecular weight distribution using GPC, low molecular weight compounds were distributed in waste mushroom logs. Based on these results, waste mushroom logs have enough potential as material for developing alternative energy because of easily conversion to sugar by various hydrolysis methods and requirement of low energy consumption during size reduction.

• Journal of Forest and Environmental Science
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• v.40 no.1
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• pp.35-42
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• 2024

The Japanese larch (Larix kaempferi [Lamb.] Carriere) is a major timber species in Korea. However, studies on bucking rates and merchantable logs of this species are insufficient in South Korea. To bridge these gaps, in this study, the bucking rate of Japanese larch (Larix kaempferi [Lamb.] Carriere) was computed and the number of long logs and merchantable log volumes were analyzed. Sample trees were bucked according to the log grade for trading, and collected from a forest field in Gangwon Province. The bucking rate of all Japanese larch logs was >89%. The highly profitable 2-4 logs of 3.6 m length from trees with ≤30 cm diameter at breast height (DBH) and 5-6 logs with ≥34 cm DBH were produced. The bucking rate of long logs was >84%; thus, Japanese larch was found to be suitable for the supply of high-grade timber. Additionally, to follow reasonable wood supply plans, merchantable volume tables were offered based on 3.6 m-long number of logs and small-end diameter classes. Understanding the proportion of merchantable log volumes, bucking rates, and the number of long and short logs has large-scale applications in practical forestry.

• Journal of the Korean Wood Science and Technology
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• v.18 no.3
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• pp.53-68
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• 1990

This research has been executed for maximization of lumber yield and more efficient use of small diameter logs. Sample logs from thinnings carne from densed artificial stands at the Kwangnung Experimental Forests situated in the central region of Korean peninsula. Species of sample logs were obtained to execute sawing and strength test for larch, and lumber strength test in full size for pitch pine and Korean pine. A survey on sawmills consuming domestic logs was carried out to know sawmill production, costs and utilization structure of lumber as a guide to business analysis. Results showed that sawing pattern from small logs less than 15cm in diameter was necessary to cut 9cm by 9cm square per one log in order to obtain high lumber recovery and provide for wide market needs. The total lumber yield of squares plus side boards was 56 percent to 58 percent from small logs and the yield for log sweep in 30 percent decreased by 24.5 percent in sawing production, compared to yield for straight logs. In sawing efficiency, production of lumber by twin band saw could be improved 238 percent higher than lumber of the same species produced by conventional sawmilling methods, and sawing accuracy with twin band saw was much higher at the lumber production than band saw. Lumber from the small larch logs has shown 70 knots per $m^2$ on its faces and also lumber showed lots of face checkings by air drying on the yard, compared to other species. MOR in bending of lumber in full size from small logs of larch was found ranging from 380kg/$cm^2$ to 460kg/$cm^2$, resulting in 40 percent less than the strength from clear small specimens. In lumber containing knots, cross grain, etc, longitudinal stress wave speed was delayed about 48 percent by defects in lumber from both larch and pitch pine logs. The surveyed sample sawmills consumed the domestic logs at the rate of 54 percent to 84 percent in the total timber consumption, showing high consumption at mills located in the mountains.

• Journal of Forest and Environmental Science
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• v.33 no.3
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• pp.233-238
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• 2017

This study was carried out to figure out the number of logs for sawtimber by DBH and height class and to compare merchantable volume ratio by categorizing into sawtimber, lagging board and pulpwood, and others for Pinus densiflora, Pinus koraiensis, and Larix kaempferi. Logs for sawtimber were hardly produced in small DBH class of three species, but produced evidently from medium DBH class. In large DBH class, the number of logs for sawtimber were noticeably different among species: 4.3 logs for L. kaempferi, 2.6 logs for P. densiflora, and 1.0 logs for P. koraiensis on average. Similarly, merchantable volume ratio for sawtimber were largely different among species in large DBH class with higher than 15 m: 82% logs for L. kaempferi, 60% logs for P. densiflora, and 44% logs for P. koraiensis. When compared to the upper diameter and upper height by species with regard to the last log of a tree produced for sawtimber, upper diameter was smallest with 14.1 cm and upper height was highest with 12.2 m in L. kaempferi. Overall, L. kaempferi was considered as the more commercial species for sawtimber production than P. densiflora and P. koraiensis.

• Journal of the Korea Society of Computer and Information
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• v.23 no.10
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• pp.11-21
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• 2018

In this paper we propose a novel log template discovery algorithm which achieves high quality of discovered log templates through iterative log filtering technique. Log templates are the static string pattern of logs that are used to produce actual logs by inserting variable values during runtime. Identifying individual logs into their template category correctly enables us to conduct automated analysis using state-of-the-art machine learning techniques. Our technique looks at the group of logs column-wise and filters the logs that have the value of the highest proportion. We repeat this process per each column until we are left with highly homogeneous set of logs that most likely belong to the same log template category. Then, we determine which column is the static part and which is the variable part by vertically comparing all the logs in the group. This process repeats until we have discovered all the templates from given logs. Also, during this process we discover the custom patterns such as ID formats that are unique to the application. This information helps us quickly identify such strings in the logs as variable parts thereby further increasing the accuracy of the discovered log templates. Existing solutions suffer from log templates being too general or too specific because of the inability to detect custom patterns. Through extensive evaluations we have learned that our proposed method achieves 2 to 20 times better accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.486-503
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• 2023

Logs play an important role in mastering the health of the system, experienced operation and maintenance engineer can judge which part of the system has a problem by checking the logs. In recent years, many system architectures have changed from single application to distributed application, which leads to a very huge number of logs in the system and manually check the logs to find system errors impractically. To solve the above problems, we propose a method based on Message Middleware and ATT-GRU (Attention Gate Recurrent Unit) to detect the logs anomaly of distributed systems. The works of this paper mainly include two aspects: (1) We design a high-performance distributed logs collection architecture to complete the logs collection of the distributed system. (2)We improve the existing GRU by introducing the attention mechanism to weight the key parts of the logs sequence, which can improve the training efficiency and recognition accuracy of the model to a certain extent. The results of experiments show that our method has better superiority and reliability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.1-8
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• 2019

Among the methods for extracting the most appropriate information from a large amount of log data, there is a method using inductive inference. In this paper, we use SVM (Support Vector Machine), which is an excellent classification method for inductive inference, in order to determine the ranking of intrusion logs in digital forensic analysis. For this purpose, the logs of the training log set are classified into intrusion logs and normal logs. The associated words are extracted from each classified set to generate a related word dictionary, and each log is expressed as a vector based on the generated dictionary. Next, the logs are learned using the SVM. We classify test logs into normal logs and intrusion logs by using the log set extracted through learning. Finally, the recommendation orders of intrusion logs are determined to recommend intrusion logs to the forensic analyst.

• Journal of Korean Society of Forest Science
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• v.6 no.1
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• pp.37-42
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• 1967

This experiment was carried out to study the peeling effect affecting to the natural seasoning by the treatments such as complete peeling, outer bark peeling (attached inner bark) and non peeling for the logs felled in summer and winter season in the stand of about 40 years old pitch pine, located in Kwangyang College Forest, Chollanam-do, Korea. According to the results this study may be concluded as followings. 1. Although the complete peeled logs are seasoned rapidly as compared with the outer barked and non peeled logs but they are more developed seasonal checking. 2. As to the drying effects of the logs felled in summer season, the difference between complete peeled and outer barked or non peeled logs are recognized. Whereas, the difference between outer barked and non peeled logs was not recognized. 3. As to the drying effects of the test logs felled in winter season the difference between complete peeled and outer barked logs were not shown, whereas, the difference between complete peeled or outer barked, and non peeled logs was significantly recognized. Accordingly it is considered that the drying effect of outer barked logs is same with those of complete peeled logs. 4. In this experiment it is expected that the complete peeled logs of summer season felling, and complete peeled or outer barked logs of winter season felling were attained equilibrium moisture contents within four months.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.60-68
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• 2003

In forest products industry, a variety of nondestructive evaluation techniques are now being used to assess the mechanical properties of structural lumber. Ultrasonic and longitudinal vibration technique are frequently used to assess the modulus of elasticity(MOE) of lumber. The objective of this research was to evaluate the MOE and modulus of rupture(MOR) of small-diameter of Larix log(Larix kaempferi Carr.), using these techniques. In this study, 50 small-diameter logs were nondestructiveively evaluated. The dynamic modulus of elasticity(Eu) of the logs was first evaluated, using an ultrasonic method. After ultrasonic tests, the logs were measured using a longitudinal vibration technique(Ev). Static bending test was then performed on the logs to obtain the static modulus of elasticity(Es) and modulus of rupture of these logs. In general, the dynamic MOE (Ev) of logs was closely co..elated with the stati, MOE for log. Based on the results of these experiments, it can be concluded that small-diameter Larix logs can be successfully evaluated by Ultrasonic and longitudinal vibration technique. The experimental results indicated that the ultrasonic technique is effective to the log, which contains many knots. The longitudinal vibration technique is effective to the log, in which many cracks are included.

• Mycobiology
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• v.42 no.3
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• pp.279-281
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• 2014

Severe bark decay disease was observed on oak logs at a shiitake cultivation farm in Geochang-gun, Gyeongnam province. The symptoms observed were fruiting bodies that had developed on the top and side surface of oak logs. As a result, the bark came off easily exposing the sapwood. Slime mold specimens collected from oak logs showed developing fruiting bodies comprising of stalks, hypothallus, capillitium, and columella, and the causal agent of bark decay disease was identified as Stemonitis splendens on the basis of morphological characteristics. To our knowledge, this is the first report of Stemonitis splendens causing bark decay of oak logs used for shiitake mushroom cultivation in Korea.